Ok, for starters, all this information is about level 80 PvP, as a rogue.
Talent Build: Mutilate/Prep 41/5/25
Stats:
AP: This is your highest priority, you want burst.
Crit: This goes along with AP, not as important but take it where you can.
Hit: Try and be close-ish to the PvP hit cap, which is 5%.
Expertise and Haste: Don't worry about it, doesn't hurt though.
Armor Penetration: Nicer than Exp/Haste, but still don't focus on it.
Resil: Resilience is a tricky balance. You want to have enough you won't be bursted down in a few GCDs, but it shouldn't be needed to get a lot. Try and be in the range of 400-500. A bit more or less will probably be ok, but if you have less you may have to play more defensively.
Gear:
You want a balance of PvE and PvP gear. Enough PvP to be in the ideal resil area, and enough PvE to be able to burst people down. This really depends on how far progressed you are in both, so just go for as much AP and crit as you can within the resil range.
Always gem offensively:
Red/Prismatic(eternal belt buckle) sockets - +AP
Blue sockets - +Stam/AP
Yellow sockets - +Crit/AP
(AP, attack power, is your friend!)
Misc. Gear:
There's a few pieces that aren't too hard to get you should aim for.
Titan-Forged Rune of Determination - Replace your "regular" PvP trinket with this, easy to get.
Darkmoon Card: Death - Your other trinket, can cost a bit (usually 800-1200, depending on your realm) but trust me, it's worth it. High proc rate, 45s internal cooldown. So it's pretty much +2k damage to your opener.
Direbrew's Shanker 2.0 - Not absolutely needed, but since it's brewfest you shouldn't have too hard a time getting one. I use this along with Sinister Revenge and it's 2.0 speed is really outstanding, more damage from your mutilate, even though it's lower DPS.
Enchants:
If you are an engineer, congratulations! It's about to pay off. Rocket gloves are amazing, use them for that extra bit of burst. The nitro boots are the best foot enchant as well.
If you aren't, don't worry.
For your weapons, get Berserking (if you can afford it, else mongoose) main hand, Titanium Weapon Chain off-hand.
The rest is pretty obvious, go for damage stats.
Icescale Leg Armor is a must.
Actual Playing!
That pretty much covers the gear, so now on to the strategies. There isn't a set "rotation" a lot is just however the fight goes, so the best thing you can do is learn your abilities, keybind them, and react.
Learn your abilities
I'm now going to go over your main PvP abilities.
Mutilate - Your main damage and combo point builder. Basically spam this to kill the enemy faster. Stop using it at 4 combo points, which usually take 1 or 2 mutilates depending on circumstances, and go for a finisher.
Kidney Shot - One of your most useful abilities. Try and always use it with 5 combo points to maximize it's use between cooldowns. You will usually use it after Cheap Shot, To Interrupt a cast, or when your target (being a healer) is about to die (which can mean from less than ~40%, since this ability last up to 6 seconds).
Cheap Shot - Almost always your opener, pretty self explanatory. Note: when you are fighting another rogue, try and have kidney shot RIGHT after it wears off, even if you cut off a half a second from cheap shot. I'll go over why this matters later.
Garrote - This is sometimes your opener, if you're against a mage, use this. Because if you cheap shot, the mage will blink out, with this you get a few seconds of burst on them, and the dot.
Kick - One of your most useful abilities, have it readily available to interrupt spellcasting. Pretty general ability.
Blind - This is one of your big CC (Crowd Control) abilities. Mostly used in arena. If you're with a frost mage you'll need to coordinate your CC. If you are with a healer you can use this on the enemy healer, or one of the DPS, to finish off the other one, or get them off you're healer. This one has many, many uses. If you get a sap off, and plan to kill the not-sapped target, use this to CC them after sap wears off, though it may often be trinketed.
Sap - Use this to CC one target, while you kill others, use it before the fighting begins.
Eviscerate - One of your big burst damage moves. It can do big damage. Use this one to finish off an enemy, or just dump some combo points into damage. Goes very well with five points and Cold Blood.
Cold Blood - Some very nice on-demand burst. Use it with a 5 combo point eviscerate unless you absolutely have to. Save it for when the target is almost dead and you need that little extra burst.
Feint - Very, very situational, but you need it. The threat reduction is obviously useless, and you won't be AoEd much in the arena. But you remember those warriors? They have Bladestorm, and it hurts. When the warrior starts spinning, use this along with cloak of shadows (glyphed) and they'd do more damage meleeing you.
Cloak of Shadows - This has such a wide variety of uses I can't even begin to describe it. From frost mages to warlocks. Most useful when you have a dot up (Does NOT remove bleeds, be careful!) and you want to vanish. Cloak then vanish so it won't be broken on the dots.
Now, I haven't gone over everything, but these are your core abilities, and the rest of them are very self-explanatory on their usage.
Keybind them:
Really, really, really, you need to. Clickers are bad enough, but as a rogue it's suicide. Even if you don't have your keyboard all mapped out, you need some keybinds, for example. I have my trinket bound to F, and dismantle bound to shift+f. I have 1-0, I put the abilities I need to get to quickly on 1-4, sorta quickly 5 & 6, and then I have shift+1-0. So it's like having two different bars that pressing shift switches between. (I raid like this too)
React:
Sorry, here's the part I can't do for you. This is just going to take practice and learning all your abilities well.
If you REALLY want to just work on your speed, play this until you improve.
That's all for now, I may add more later, but I hope you enjoy this guide and that I helped someone.