There are some really good steps to improve your reaction/skills etc..

1. Don't be afraid of anybody (Most people just camping in the houses and doing nothing until it's 1 vs 1 and he probably loses)
2. Everytime aim for the Neck/Head (Just to improve your aim better keep on doing that and plus it you'll do more damage than just shooting randomly at the body.
3. Play 6-8 everyday (I don't recommend it to everybody it's just for those who really want to be good at the game and improve their skills such as reaction,aim etc..
4. If you're below 50-70% of your health you MUST! Heal yourself no matter of what will happen you gotta heal yourself just in case something happens.
5. After all of those steps you're good to go! Now get in the car while in game and just rush everybody with a shotgun ;)


With love,
Bratva✙Striker