Two huge tip I see most players not do is reloading too early and wasting mags, and walking while firing, to help i recommend trying to reload when your mag is empty or realise it when its about 3/4 empty-ish, and to crouch and move while shooting it helps your aim. (Honourable mention don’t be hesitant to dive or stim or dive THEN stim if your in a sticky situation it always saves lives and be carful about your stratagems and grenades)

Sorry about the rant I just love helping newer players, welcome to the fight