How do I become better...?

Alright, so I've been playing FPS games for about 6 years now on most platforms. About 3 years ago I switched to PC, but I still occasionally hop on the PS4 to play games my PC simply can't run. A trend across all of the platforms that I play on is that I'm absolute garbage.
That being said, I'm looking for FPS tips that I could apply to better myself as a teammate, and a gamer in general.

 

practice
no pain! no gain!

 

for me it was to just play more and focus on what others are doing and try to do a similar thing to what they are doing, and also just practice

 

Practice is obvious with practice you will find the pattern of how the game flows.
more important this is my true experience. i played FPS game since Counter Strike back in 2006, what you need to find to be good player or good team is to find your sensitivity of your AIM. if you using controller find the better sensiv that suits you that goes for Mice as well.

personally i used low sensiv for most FPS Comp Game

COD:
Mice sensiv: 400 DPI
in Game :17

OW:
Mice sensiv: 800 - 900 DPI
in game: depends on Hero Roles

Valorant:
Mice Sensiv: 700 DPI
in game: default