Well i play a druid/hunter and we are in the early 1600 (decent i guess). Well my partner was surfing the web on startages to win against the dreaded warlock/shadow priest (constant fears would mean nobody got heals).
But instead what my partner found was that, plus how to win against other popular comps. There are some for other 2v2 setups and for 3v3 ( i haven't checked for 5v5).
They get a team that has got a high rating for that setup, and show you how to win against teams you might be having trouble with.
Here is the link: Arena Junkies - World of Warcraft PvP Strategy and Discussion
I do NOT in any way want to take claim for making this site, im simply bringing it to mmowned.