When sniping in multi-player mode, it is best to do the following. Always snipe from tall grass or off the side of a hill. Never snipe in plain sight or from an easily viewed place, such as the top of a hill. When you see or hear shots fired at you, either duck and wait for at least twenty seconds, or run and find a new location. It is wiser to run to a new place, since the person who is shooting at you is going to either do it again, or find you. Also while sniping, it is wise to either place two claymores behind you (facing away from you) or to lay on two satchels. This "revenge" tactic works because if you use the claymores, you will get the guy for even thinking of killing you; or if you use the satchels, you can ignite them immediately after you are killed, respawn, and kill your killer. Also, do not shoot rapidly or you will give you position away. Another way to catch the someone trying to kill you is to use one of the third person view perspectives while shooting to see what os going on around you. As for assaulting or flag running, jump a lot.