Okay, I just read that other so called Rogue duelling guide and nearly cried it was so horrendous. So I thought I'd bring you some proper tactics on how to beat classes both in PvP and arena, this is probably gonna be a very long post so I'll try to cut it up into sections so if you want to read up on a specific area you can.
Disclaimer: I'm going to try and be very specific so those of you that have never played rogue or are just new to rogue/WoW can take information that may not be rogue specific. Also I'm not posting actual specs, as I don't see the point, we'll all have our own variations and twists on a spec so you might aswell check other people's out via the armory and then see what you think is best.
Mutilate specs
41/20/0
This spec is generally seen as the PvE Muti spec, it's got good sustained due to the Dual Wield Specialisation, but that doesn't mean it's better for PvP just because it does more damage, a lot of the time you won't be sitting on your opponent you'll be chasing them, obviously this would out damage a Assass/Subt Muti build in PvE because you can just sit there keeping your cycles up and DPSing. The advantage is does give over a Assass/Subt build is the fact you have Improved Sprint, so if you're not a gnome you can break an extra snare. Woot.
Definitely the mutilate spec I'd take for 2v2 in a double DPS team.
54/0/7 or 51/0/10 (Whatever Poison Heavy Mutilate spec you want to go)
This spec is all about making sure your opponent has Wound and Crippling on as much as possible, what you lack in mobility you gain in giving the rest of your team either a 5 stack of Wound, so there damage isn't getting healed as efficiently, or because crippling is stuck to them so the target is forced to fight with you instead of going for a target that's causing them more problems (A healer a ranged DPS that the other team wants to zerg, whatever)
The 3v3, 5v5 Mutilate spec. You can deliver huge burst DPS, but with Imp Kidney Shot you're upping your teams DPS a fair bit for shatter combos and whatever. Also if you're running a melee train setup in 3v3 or 5v5 take improved Expose, that extra 1k armor pen is gonna cause some pain.
Shadowstep Specs
20/0/41
This spec has Vile Poisons, either 4/5 or 5/5 depending whether you want 4/5 or 5/5 in Lethality. This is sort of the shadowstep equivelant of the mega poison mutilate build. This is the spec most of the top ShS rogues are running, and also the one I'm using between 2000 and 2200 in 2s. It has replaced AR/Prep as the only spec to use really, but there's still a few people holding onto Muti specs and doing exceptionally well with it so don't feel you have to spec this just because everyone else is.
There are variations of the Shadowstep spec, I'm not going to go into them because I don't feel it's necessary, taking Imp Evis and Master of Subtlety to get more burst from stealth by doing "Premed, Shadowstep, Cheapshot, Evis". But I believe you're losing too much in doing this just for a little extra burst.
1v1
Okay, your 2 main specs are Mutilate and Shadowstep. In 1v1 I'd say 75% of situations are gonna favor Shadowsteps mobility and survivability, but certain classes are gonna be about equal regardless of your spec.
Druid
Okay, Druids are going to be a pain in the arse with either spec, and pretty much regardless of their spec aswell.
Feral
The problem you're going to face here, as with any druid fight, unless they don't start in cat for whatever reason, is not being able to get off a sap. Opening with a sap as you will see throughout the 1v1 section isn't vital, but it's a huge help. I'd say just wander round in stealth as if this was a rogue and spam cheap shot, don't try and garrotte, this is one of your best chances to unload alot of damage. If you catch them in cat they don't have the huge amount of armour they do in bear, and they're not full of HoTs. If you can open with cheapshot don't bother chaining it with Kidney Shot just yet, I'd advise Expose or Rupture
If you've duelled the druid before you'll know whether they're most likely to jump into Bear and just tank you, or if they'll jump into caster and try to cycle, hot up and get an advantage. If you know they're going to jump into caster form try and get a kidney shot off, they will most likely trinket, but that means you've got a chance to use blind within the next 2 minutes for a bandage and/or restealth. Okay, so by this point depending on how things have gone your target should be on between 50-75% health, depending on how much damage you got out during your cheap shot etc. This is where the fight really begins, it's all about just keeping at it and not stopping, keep rupture up if he's in bear and hoping he'll switch out and you can get a kidney shot off. This isn't so much a war with his mana, but a war with how low you can go without panicing and being aware of your cooldowns etc, Obviously if you're on 5% and your cheat death has procced (or your muti) and evasion has 2 minutes and blind has a minute left, you're highly unlikely to win, but you never know.
A little tip while duelling tauren druids (This isn't spec specific, it's fairly universal for druids), if they go out of bear and cast war stomp, try and kick, lag can cause it to hit the cyclone, so you'll be stunned but due to lag you've interrupted the cast of cyclone, I'm not saying they're going to use cyclone straight away, but even if they go into travel form and run, you've not wasted it because by the time you catch up it'll be off cooldown or they'll be in bear and it's pointless then.
Boomkin
This is virtually the same as fighting a feral druid, apart from there's more stuff to interrupt, to be perfectly honest there's no good Boomkins on my server so I've never had to really try. Sorry this isn't as detailed as the feral section.
Resto
The PvE equivelant, with warlocks of Kil'Jaeden, an absolute pain to kill with so much effective 1v1 CC, mobility and healing. Basically this is a battle of stamina, can you outlast his mana or can you time that kidney shot perfectly to nuke down the last little bit of his health, both Mutilate and Shadowstep shine in there own ways here, that final Kidney shot can be truly devastating with Mutilate, especially if you get a Cold Blood Mutilate and another 1/2 Crit or 2/2 Crit Mutilate, and with the huge amount of poisoning going on he's going to have to go over time into shapeshifting and abolishing poison. Whereas shadowstep you still have fairly good poisons and if he does get away, you shadowstep and you're right back on his tail.
Rogue
Mutilate
Okay, you have alot of advantages if your shadowstep, and it's obviously a fair fight if you're Mutilate. The opener should be yours if your ShS, but still you may not get it, open with Sap, it not only gives you time to think, it means you've spooked your opponent slightly, they know what's coming, sometimes they may trinket vanish instantly to get the drop on you, while this is giving them an advantage, they have blown their trinket. With Mutilate rogues you don't want to be sat in their kidney shot, while you can only break the first one, I'd advise you do, unless you've got a lot of health and think it'd be worthwhile breaking a possible blind later on. Basically if they time that Kidneyshot well, and they get lucky, you could be losing 50% of your health.
The best thing you can do is keep rupture on a rogue at all times, making it harder for them to restealth and stopping them from bandaging. If you do happen to get rupture on yourself, and you want to restealth/bandage and you have blind up, don't worry, you can always blind, time your stealth between the ticks of rupture and sap, by this point you should have had 20-22 seconds to get a bandage off, it might not be a full one but it should help somewhat.
Shadowstep
Okay, similar situation to the mutilate rogue obviously, but this time if you're mutilate you're gonna be on the recieving end of getting opened upon. The only difference in this fight is double cooldowns, and Cheat Death, once Cheat Death procs make sure you have rupture up, it's a 3 second time frame for the other rogue to run away. Rupture will get you one of 2 thing, either it will finish him off, or you will keep him from bandaging and stealthing.
Mutilate rouges have it hard in 1v1, but it's a trade off you make for being an exceptional addition to any 3v3 and 5v5 team that don't want to use or have no need for an MS warrior.
Priest
Disc/Holy
While you're not gonna find many holy specced PvP priests, I'd say Disc and holy and virtually the same, just incase you do, you have 2 options, make them waste their mana, this involves interrupting any DPS spells, and letting them literally heal themselves to death, or just interrupt healing spells and burn their health away. If you're mutilate this should be a nice and easy fight, a priest can't really kite for any valid reason so they have no reason to run away really apart from to avoid your damage and if they want to heal they have to stand still. I'd advise waiting to blow your Cold Blood after they have used Pain Suppression, or use it early to force a Pain Suppression. I have never really struggled with Priests, so unless they're exceptionally good you shouldn't have too many problems.
A post from Jellysol who knows more about priest's than me for a bit more info on them
Just want to point out in regards to priest specs. Holy & Disc are two entirely different PvP approaches for a priest. Know that if you're facing a priest that is Holy spec, he's likely lower in resilience then a Disc priest, as Disc talents do not shine until they exceed 300+ resilience.
Also to note, any Disc priest with a clue doesn't heal using anything with a cast time. Renew, PW: Shield, PoM, Pain Supression are all instant cast and can't be interrupted. The only time a priest with a clue will bother 'casting' a heal is when they have their target feared or if they know that their opponents interrupts are on cooldown.
With the changes to Reflective shield not breaking CC, a large majority of priests are now making this talent a staple in their builds, and as such melee fights are a joke. Try to save large bursts for in between shields & use weak attacks to keep prayer of mending from healing too much.
Shadow
One of our best Season 1 2v2 partners, is now easy meat. Basically just nuke the crap out of them, try to lock them down completely if you can, shouldn't be difficult as their survivability is dire and unless left alone their DPS isn't all that great either.
Mage
Okay, I'm gonna say 90%+ of mages are Frost, and PoM mages are too easily mitigated by CloS and Vanish if used well so I'm not going to bother covering them.
This is one of the hardest fights for any melee class, so prepare for an epic battle.
You want to start with sap, chances are the mage is jumping around spamming arcane explosion rank 1 or standing still doing Blizzard rank 1 all over the place, if you're mutilate you may or may not have the talents that increase sap range, either way try and time it between arcane explosions or avoid the blizzards, once you have sap off you've got a small advantage. Open with Garrotte and start DPSing, you have a chance now to get out some DPS with no casting, I'd advise using eviscerate or expose armor here, depending on what you feel is the best for your spec, they may blink they may not, but the basic principle is to get them to use Ice Block asap, much easier with Shadowstep, as soon as they blink, Shadowstep Kidneyshot, they'll probably ice block this, if the pet is up blind it, a running mage isn't a threat, but that pet is a real pain in the arse. So blind it as soon as IB is used, that'll mean the mage either has to resummon another, which is obviously forcing a cold snap, but it's also giving you time to bandage while the mage is ice blocked, which means they either have to get out of IB straight away or let you heal.
If you time it well, their blind should still be on cooldown from your Shadowstep Kidney shot , which will means they'll be hesitant to leave ice block, but depending on your health they might be forced to do so.
They're the general principles of mages, it's always going to be a tricky fight, depending on your health trinket can be better used on polymorph or frost nova, if you're low and you get poly'd save it, he's healing you (Or was that changed in the patch, not sure if it was PvE only) if you're on low and you get nova'd though, you could have an incoming shatter combo, which is bound to hurt, so might be best to CloS or trinket depending, use CloS if you have it but trinket if you don't.
Warrior
The only worthwhile warrior Pvp spec is MS, so nothing else is gonna be included.
Chances are your warrior friend is gonna use blood rage and then use piercing howl if he sees you, if he does pop blood rage stay away from them and let their rage get back down to 0, chances are you'll be feeding them rage most of the fight, so don't give them more than they need :P
Open with garrotte if you can then get a rupture on them asap, once their rage is getting towards 30 pop Evasion, don't refresh your DoTs now, you want to use stuns, what I try to do is, use a 3-5 point evis depending on how much energy I have, then save 5 point for KS at the end of my Evasion, this fight is all about mitigating all of the warriors damage while you unload on him, if you're shadowstep you want to save ShS, if he gets intercept on you it could be game over especially if he's using it offensively, he knows you're low and you've got to play defensively, he gets intercept then he gets a sword proc/mace proc off his white and an MS in and you could be in trouble, basically if he's getting away from you and you have ShS, use it, sometimes it's better to just go all in towards the end and hope for the best, you can do what some rogues do, use it as they intercept, obviously that's the best bet, but if you're reading this I'm guessing you're no 2.5k rated rogue who is a whirlwind of death because I'm most certainly not nor do I claim to be, and if you time it wrong you're getting intercepted anyway.
Mutilate rogues are once again at a disadvantage here, due to not having double cooldowns, but at the same time they have alot more burst for example the warrior's virtually dead, and you have a good chance of bursting him down in a single Kidney Shot, whereas with a bad streak of non crits an ShS rogue might not get so lucky, also you can keep up, rupture and expose armor throughout the fight, so if you play it well you make your own advantages.
Shaman
The only shaman's I don't like duelling are resto ones, they make me QQ.
Enhancement
A melee shaman, don't make me lolz, these guys are easy mode, I'd say totems don't even matter, consider taking out the Windfury, other than that just keep Evasion up and burst them down, if they try to heal interrupt it with a kick, gouge or kidney shot, they're bound to die anyway.
Elemental
A bit like their enhancement brothers, but they can cause you alot of problems, remember they have +healing aswell, so their heals are going to heal them unlike an Enh shammys heals. So stopping their heals is more important in this fight, also keep their Poison Cleansing and Earthbind totems down, these guys can do DPS from afar, and Wound will help you in this fight. You can out mana Ele Shams, basically kick any DPS spell, but let them heal, this is risky because of their instants, you'll also have to take down every totem you see to make them waste mana recasting them.
Resto
Possibly as horrible as a druid fight, but sometimes as easy as a shadow priest, this fight is all about locking them down, but with Earthshield they don't even have to heal to keep themselves up to an extent, EVERY totem needs to stay down, this is to make them both waste their mana and time getting them back up, if a totem poses you no threat because of distance or it's effect leave it to interrupt a spell or get some burst DPS in, this is going to be a long fight most likely, and will require blinding to get a bandage off if the shaman is good, but again it's just another keep working at it and you'll get there.
Little note on totems, don't waste energy on them, just click and wait for a white attack, or use your thrown weapon.
Paladin
Alot of people seem to complain about paladins, but I've never found them a major threat. On my server they do seem to have the most arrogant player base though.
Retri
These guys can really unload some DPS on you, make sure you use Evasion, this doesn't affect their holy damage, but with a 2h they can hit as hard as a warrior with white. Basically you're trying to force a bubble or heal, if they start healing interrupt it, it's the only think you'll be kicking against any form of paladin.
They'll probably start off standing in conc, you can just move jump and spam cheapshot in the air and you should get them, or garrotte or whatever you choose to do, jump right from the very edge though or it might catch you as you land. As soon as they bubble you should know if you've won or not, chances are they've trinketed a Kidney Shot and if you're on 60% or above, it should be a win, as soon as they bubble, get away from them and vanish, now they're stuffed really, yeah they can heal, but they know you've just made them bubble and you're still (hopefully) above 60%, as soon as bubble drops get back on them, they could be mid cast of a heal and you could be a fair distance away, if you're mutilate you might want to sprint unless they're on 85%+ they could still get the heal off and it'll barely make any difference, but if you're going to keep them from getting a large portion of their health go for it, if your ShS you know what to do by now :P Get right back on them and stunlock them now, they can break it. Should be yours as long as you keep up interruptions etc.
Holy
This is a fairly simple fight, both of you are trying to grind each other down, the paladin's DPS is going to be very little, but with plate, heals and bubble, his survivability is very high, you are working to a similar principle to the Retri fight, get him to bubble and the fight is yours. Holy palas only really serious form of DPS is Holy shock which I believe hits for around 800-1200 so it might not seem like alot, but when the bastard won't die it's still something to watch out for. Interrupt his heals and just keep going with the DPS. It can be won regardless of what alot of people say.
Warlock
Some say they're the gods of PvP with too much CC and the best for of damage, I say "Lolcakez, eat Roguez power". Anyway, this is pretty much one of the best fights you're going to have, it's either going to go astonishingly well and you'll eat them alive, or it's going to go horribly wrong and you'll die.
Destro
If you're undead, welcome to easy mode, if you're not, this fight can be a little more difficult, it's your choice whether you kill the succy or not, or just blind it, it should give you enough time to cause the lock enough problems where as he won't be able to surive if you use CloS, just go all out nuke mode, but use KS if you have it on the lock, it isn't worthwhile letting him get a fear in because that's gonna cause some major problems, the burst DPS destro locks can unleash is something most classes can dream of. Lock them down and stick to them and you should come out on top.
SL/SL
Again, for undeads generally an easy fight, the rest of the rogue population is probably gonna have to work a bit more though. They might start with a voidy for sacrifice, which is another 4k damage you've got to do, or they might even be naughty and start with sacrifice up then summon a felhunter, if they do this wait for Sacrifice to drop. Focus interrupts on fears, you have 5 interrupts for fear, CloS, Vanish, Kick, Gouge and Kidney shot. Use whichever fits the situation best, for example, a full set of fresh dots, use CloS, might aswell make them recast all of that again. Try to keep them locked down as much as possible, fear is your main problem, DoTs are pretty much going to be on you regardless, but if you get feared then have to eat a shadow bolt on top of that it could turn the fight.
Demonology (Felguard)
This fight will start with the warlock standing away from his Felguard, if he is you're going to get intercepted, but don't let it be the focus of all your attention, make sure the lock has crippling on him, if he uses intercept as soon as you come out and you have cheapshot on him he's wasted it, if he's a good lock he's going to wait for cheapshot to be close to it's end, at which point you should have 3-5 points on him and also crippling, if crippling is on him you've got a good chance of getting back on him, if not it might be time to sprint and possibly CloS if they decide to try and fear you..
Once the intercept stun is over pop Evasion, that Felguard will hurt you, so try to mitigate it but don't put crippling on him, if he gets too far away you're getting intercepted again. Try and get back on the lock, in this fight you can go for a more DPS kind of approach, but still, don't go so DPS you end up getting feared due to no energy or GCD when you should have kicked.
Hunter
All hunters are the same, they're going to do similar things and try to kite you, so there'll be some basic tactics, then a little more of The "Skill" Within hunters.
The hunter will be sitting on a flare and a trap, it'll be a freezing or a frost trap, you can either hope for a frost, or take it that it's going to be a freezing trap (That's the one that puts you in an ice block) basically, if your shadowstep it's still possible to get the opener, if you're Mutilate, I'm afraid it's bad luck again, and even more bad luck if the hunter is Beast Mastery specced. Use Premed and CloS and Shadowstep, then spam whatever button you want to open with, you should land it, make sure you get crippling on them, this is even more important if they aren't BM specced. If they're not BM lock them down with stuns, remember if they trinket Crippling won't be on them and they'll probably have you on a frost trap so get it back on them, if they do get away ShS to get back on them, be careful of traps, they can be a major irritation and they are going to be what you'll be fighting against more so than the hunter himself.
The Skill Within hunters are in 90% of cases going to break your opener or first kidney shot with their mad skills, as soon as they do this get away from their flare, you can either ShS to them and then turn around and run away, then use CloS to get rid of Hunters Mark / Serpent's Sting and Vanish, they could try and flare you but if you use sprint or still have the ShS buff hopefully they won't get you, MAKE SURE THE FLARE DEBUFF HAS GONE if you don't vanish won't work and you'll probably die, once TBW has gone you can reopen and the fight should be yours, with Evasion you shouldn't have too many problems but still they can kite you, so use ShS if they ever start getting away.
General Tips (These might be my own or could come later in the thread)
Fake Casting:
Any caster worth their salt can do this, basicall y they'll start casting to lure you into using your interrupt, but between 0.1 and 0.5 seconds of casting they'll move to cancel the casting, so as you've pressed your interrupt, they've stopped, and you've wasted it.
Poisons:
What poisons to use and where! My general setup is, Wound Main Hand and Crippling Off Hand. Depending on who/what you're fighting you might wish to change this, Instant, Deadly and Anaesthetic don't belong in PvP, there is never really a situation when any will out perform Wound and Crippling so don't use them is my advise. Mind Numbing can work, for example against a pure DPS caster, to increase their casting times, but still, changing poisons for one fight is never worth it, chances are you won't get the chance to do so in a BG/Arena and if you do you'll end up wasting alot of poisons, so get used to killing them with Wound and Crippling and then you shouldn't have too many problems.
Gear & Skill:
Obviously if a player vastly outgears you or is a much better player you're not going to win instantly, but don't worry about it, keep trying and eventually you'll know instictively what to do.
Q&A Section
Okay that's all for now, my arms are hurting from typing so much, but I felt a good rogue guide was needed, and the other one that was posted is dire.
I'm expecting a fair few "Wall of text crits you, you die" but there's alot of information here, so hopefully some people will find it useful.
If you want to reuse any part of this guide feel free too, if you don't give me any credit you don't, that's upto you, obviously it'd be much appreciated if you did, or is you just said it wasn't originally your work, but I'm sure others will throw it around freely claiming it's their work, and that really doesn't concern me, I won't ever meet you, I won't ever talk to you, so I won't ever have to deal with it in the real world. And I'm sure most of the people from here won't do this, but if I ever see my work without credits, I'll just think, "Wow, someone thought my work was so good they're claming it's their own"
Feel free to post questions and I'll add them to my Q&A section if I feel it'll be helpful, or if I've missed it out. Good luck all you rogues with your PvP fun :P