i sometimes find moving all the time gets you killed lots – you need to assess your opponents. sometimes there are muppets who'll go hell for leather to kill you, so if you sit in place A and kill them, they will go straight back to place A again to get you. Meanwhile you've moved a short distance away to B and placed a betty at A 🙂 They lose a limb of 4 and see you sniggering on the killcam located at B. They'll then try to get you at B, probably by trying to get behind you. Move to A or C and betty B up and continue until they are foaming at the mouth.
IME keep low, sprint where the coast is clear but walk otherwise – you cannot shoot whilst sprinting. dont run across huge open areas (i.e. use cover where available and sprint between) learn the maps and more importantly the spawn zones (stops folk spawning behind you and slotting you straight off) sort your controller options so you can move the sights quickly but not so quickly you have no control. find a gun you like and use it appropriately on the maps (dont use a sniper rifle on a small map unless you are very handy with it)
above all, dont let your emotion get too high otherwise you end up throwing lives away trying to get someone who is better than you, and probably giving them dogs (or new quivalent) which will just waste you more.
🙂