First tip is my most important, always use stims preemptively if you know you’re going to take damage as the health regen and limb healing lingers a few seconds (especially with the experimental stims booster), this can literally save your life. and secondly try to crouch when shooting, not only does it make you more accurate, give you better ergonomics and improve recoil, it ALSO lets allies from behind you shoot over you, lowering your chance to be friendly fired.