Take the time to practice all of these things by yourself, in a practice game or against bots
- Mindset - protect yourself first and be unaffected by enemy gunshots
- Control - every movement in battle needs to be deliberate, and perfectly executed
- Take Cover - a single mistake here will cost you your life
- Dodge Bullets - know how to sprint from cover to cover, with the right timing
- Aim and Shoot - specific strategies to improve your aim (covered in video extensively)
- Kill Entire Squads - practice your skills in a live situation against multiple enemies
where is the enemy? how many are there?
do i have good cover? can they see me? will i get hit?
where am i looking? 360 degrees? or tunnel vision?
can i get a shot in? shoot to scare or kill?
position, safety, and awareness is infinitely more important than trying to "kill someone before they can kill you" - a common mistake to make especially if you are not thinking clearly
I made a video series with some serious tactical and training/practicing strategies to help you get better at shooting games. It's a 4-part training series about an hour in total.
This one is probably what you're most interested in...
Part 2: (practicing strategies)
If you like that video you should watch the rest because they will help you even more.