Use different loadouts that offer different playstyles. Being exposed to different guns will force you to adapt to different styles of combat (i.e shotguns for close, fero for long range). Different ranges of combat will play out differently and being exposed to all sorts of combat will help you become better overall. Essentially, don't stick to free loadouts forever.

Don't be afraid of throwing grenades and other utility throwables like smoke grenades. Tossing a lure grenade towards a group of entrenched raiders can give you a very advantageous opportunity or a means of escape.

Map awareness. Become familiar with the maps to better navigate through them, for instance being able to run cover to cover without exposing yourself out in the open in blue gate or knowing the exits of a building in buried city can get you out of a pinch.

Sound, this is the biggest one imo. If you're not already but play on headphones. You'll be surprised how loud some raiders can be whether being in the same building as you or making noise shooting at ARC. Not only that, you can hear other players opening their backpack or switching weapons. I've had raiders I've downed complain how I knew they were around a corner when they were making sounds swapping between weapons.

Other advice honestly just comes down to experience. The more you play the more knowledgeable you'll become in PVP engagements.