Hip-fire only as a last resort, its works only to like 2 meters max(and not all that great to be honest). Using an LMG is pretty simple, aim using sights, go for the body, pull the trigger and control the recoil, you could try crouching if you really want, you should also focus on aiming rather than strafing around and whatnot. Its works best on short range, medium range can also work with single shots (but its not super-effective anymore). Sheer firepower of LMG will give you an edge in close combat.(even with slow ADS time, you should be able to put one bullet into enemy, before he's able to put 3 into you with his SMG)