Rufus: Very basic strategy. If your enemies know where you are, then don't be there.
A recent reviewing of this movie I picked up on this quote and well ...its just too good to not be applied in PVP games.
So move swiftly and do not be where your enemy suspects you are. This will result in a retargetting or new acquision.
In call of duty a grenade thrown can signal your location so throw and move.
In WoW there was a battle in Alterac Valley where a team could raise a Avatar to destroy the enemy but this avatar was noisy ..your enemy would know what you were doing and would try and stop you.
Shooting from a tank or a rocket launcher is a dead give away of your location.
COVER and HIDE
then light them up when assistance arrives :D