My secret for locating is a pair of Denon D2000 headphones....I use Dead Silence so I dont mix in my own footsteps....but I can hear everyone near me that doesnt use Dead Silence...its almost like having a permanent UAV using your ears instead if you can distinguish which direction they are coming from. And just for FFA by itself, it is imperative you use Slight Of Hand....you have to eliminate re-load deaths to keep your kill streaks alive, especially in a full server. In other play modes maybe not so much, but its a must in FFA.