Afflictionning

Any simple build, you must use Unstable Affliction, Fearh, Haunt and Death coil as main spells and you can use Fel Armor and Soul link as buff.
As your minion i suggest you to use the Felhunter... or the succubus... (but you can choose one from them all)
In PvP use the sequence:

Fear - Pet Attack - Corruption - Immolate - Death Coil - Haunt - Howl of Terror - Fear (ADD) - Unstable affliction - Drain Life

with that you can kill any player in PVP...
if you did use all those spells and you don't have killed the enemy, try to add another Curse and use fear many times...