No plan survives the first contact intact. Friendly fire - isn't. Anything you do can get you shot - including nothing. Professional players are predicatable but the world is full of amateurs. When you have have taken an area, don't forget to tell the other team.
Tracers work both ways.
When in doubt, empty your hopper. Never hide behind a tree thinner than you are. The only thing more accurate than incoming enemy fire is friendly fire. The diversion on the tape you are ignoring is the main attack. Try to look unimportant, the enemy may be low on paintballs.