Ok, Heres 3 tips for you warlocks in arena, Firstly when you enter the arena, Summon your Imp and give you and your teammates "Fire Shield" Pretty cool buff that 99% of locks dont know about or use, Secondly After you have summoned your imp, Summon your voidwalker. When you see the "15 Seconds to go!" thing, wait another 5 seconds and the start chargeing your felhunter, youll notice you carnt sacrifice your voidwalker when your summoning your felhunter, but at then end of the cast it becomes avalible to be sacrificed, So you now have a fire shiled, and sacrifice, Go ahead and throw "Water Breating" on yourseld and " Detect invisibility " these act as purge spells.
Another good tip is this, if you have a noob dispeller ( usually paladins do this the most but any class can ) That is constantly dispelling all your high rank spells, start casting rank 1 corruption / SL / agony and watch there mana go down quicker while yours stays at / near 100%
Another good tip is, if you meet a resto druid in the arena, and he switches to Tree form, You can banish him, it lasts about 10 seconds and you should be able to kill his partner before he even gets out of banish!
Another good tip is to NEVER have your felhunters counterspell on auto, This is because it will use counterspell on the next incomming spell, so for example a priest trys to mind blast you, he gets counterspelled, hes on 5% and he goes to heal. if your deathcoil is down he can heal himself, but if you didnt use the counterspell youd be looking at a dead priest.
Another good tip is, Rogue kiteing, If your specced with Curse Of Exaustion, what you wanna do is put some dots on a rogue / warrior, then you are probly hamstrung atm, put curse of exaustion use your insigia and kite them, rogues carnt stealth cus of your other dots and warriors have to wait 20 seconds to charge you.
If i think of more ill post.