The same old tips,
? Burst 2-3 shots, they will always be accurate if you aren't moving.
? Never crouch walk. It makes you look like a sitting duck and you will be an easy kill for your opponents
? Always check your radar. It is the greatest tool you can have, it tells where your teammates and enemies are.
? Don't move too much when you are in combat. If you see an enemy, you don't want to be moving too much while you are shooting. It will increase your bullet spread and your bullets will be all over the place. Moving around a little to avoid standing still is fine.
? Get into the habit of always aiming head level. If you get used to aiming head level it will be less work for you when you see an enemy. Instead of seeing an enemy, and then having to aim towards a headshot, you will be already in the head area and only have to adjust side to side to where the opponent is standing.