Still working on getting the right pieces from BGs, but you can copy my affliction lock:
https://worldofwarcraft.com/en-us/character/bonechewer/gotofel
Having a wand equipped gives a small boost in stats inside of instanced pvp. My wand is no longer available, but any wand works really. Use the staff from the pvp heirloom vendor or the staff from blackfathom with versatility on it for open world/pve stuff.
Basically just go for high intellect, versatility and haste. You'll have to get a haste belt from random dungeons; the one I'm wearing is no longer available.