I pulled this off the pvp forums. It's by a druid named Hazrune. He listed a few ways to use different classes and the arena environment creatively. While not gamebreaking, many of these tricks could mean the difference between winning and losing. If you have your own tricks like this, please post them in this thread.
Are you being locked down by DPS and then the rogue suddenly goes to blind your healer who already burned his trinket sealing your fate? Intervene your healer, you'll eat the blind.
Getting chain polymorphed by a mage? Fight taking entirely too long? Try and remember, Shadowsight isn't just for Roges anymore.
You find yourself fighting a druid who is in bear form and you can't seem to deal any damage. What do you do? Hamstring him and RUN AWAY. Two things can happen, either he will feral charge you giving you a second wind proc, or he'll shift into caster form in intercept range. Repeat this every 15 seconds. And it doesn't hurt keeping bandages on you to force them to do one of the two (if you're cheap, use silk bandages).
Pop quiz. What does a paladin do when he gets hit with Unstable Affliction and Viper Sting while his bubble is down? 95% Of Paladins will log on to the PvP forums and request a warlock nerf. The other 5% will cast Purify.
Shadowsight owns for you too. For the times you can't BoS.
Mind-numbing poison is amazing, but there's just no room for it on your weapons when you already have crippling and wound poison on, right? Wrong. Don't throw away that S1 offhand. Put Mind-numbing on it and make a macro to equip it to your offhand, then Shiv, then equip your main offhand. Repeat every time it wears off for a 35 energy cost Rogue CoT.
Is 45 seconds of caster lockdown ownage not good enough for you? Try pouncing healers when arenas start. Not for the stun which ultimately won't matter. That combo point will stay on him until you put a combo point on something else. When your bash and feral charge are down and your cyclones are on DR, pop into cat form and maim him. Your feral charge will be back up before he can say "wTF NErF DrooIDS".
You're in a two-DPS team and you and your partner are out of spell locks on the enemy healer. And he's either fear immuned or you can't get a 1.5 second cast off because of the rogue/warrior/whatever on you. Try Fel Dominating a new Fel Hunter. Your new fel hunter will have a fresh new spell lock ready, and it isn't like you'll be needing the fel domination for anything else if you can't get the kill.
I'll think of more for the other classes when I get back."