I'm not really good with anything that goes in the air lol. but I can give you some things to try, since I don't know what part of the game you're bad at so I'll just point out some basics and things I've found that tends to work for me.
turn on aim assist, you see a enemy in close range, aim your hip fire crossairs close to the enemy, press and hold L1 and you'll notice your gun will snap to the target like a aimbot does, soon as you see this happen open fire. don't let anyone tell you that this is either cheating or cheap, its in the game to be used so use it if you want.
know your streaghs and weaknesses are, for an example, if you don't feel safe shoot at people long range then you probably shouldn't. hip fire with shotguns, this decreases the time between seeing an enemy and shooting at them. besides it's eaiser to control the higher recoil of the shotguns.
high fire rate doesn't always mean it's better, try to stick with fire rates between 650-750 rounds per minute, this makes it eaiser to stay on target and more time to fix your aiming. with lower fire rate weapons try and keep your enemis at a distince. low fire rate weapons really shine down range.
stick with your teammates, kinda sounds mean but use your teammates as dumbies, you see them being shot at, you can find out where the gun fire is coming from while their focused on your teammate(s) and also this way you'll have covering fire when you're reloading. reviving and put first aid kits or ammo to keep your team going strong.
play on one map a lot to really get to know the layout, like find the choke points and avoid choke points at all times when you're on your own.
good luck and hope these tips helps
you're welcome. I fixed some typos so if you weren't sure what I was talking about you can re-read it to be sure . for an example, I said R1 instead of L1 lol.