don't complain about snipers
don't complain about shotguns
don't complain about rockets
don't accuse people of cheating
don't spray & pray your entire clip
don't piss me off
dont walk up to a window and just stand there. move around a lot. and if confronted, dont charge straight at a guy or whatever. move and shoot. good luck and as many have said before me, dont die.
-strafe around, especially when an enemy is right infront of you. Try to keep your aim on that person even when you're moving around. Don't just stay there and shoot. Only be still if an enemy doesn't recognize you (if you get him from behind).
-reload whenever you have time. Don't shoot away half you clip and keep going without reloading. Go behind a box of some sort and reload.
-play it slowly. Don't be the first...idiot in the group that always gets killed by incoming grenades.
Another good thing to do is think, If someone else did this would I be mad or irratated, before you do the thing. Think before you act. And dont claim some one is cheating.