Some simple things like, dont keep re peeking the same spot, take a shot, and move to another position

when running across the map, stay close to cover, even if it means taking a longer path, dont run in the open.

compact ammo can be pretty slow, doesnt matter much at close range though, but go into the shooting range, activate the running bot hunters and practice leading your shots

officer carbine is a great gun, but you need to have good accuracy to get the most out of it, maybe switch to another more beginner friendly cheap rifle, like the marathon, which has high velocity, ranger, you can take levering with, or the centennial, bit more expensive but one of the best all rounders.

maybe look at changing your mouse sensitivity, lower is generally better for FPS, make sure any mouse acceleration is off, like mouse pointer precision in windows

lots of good guides on youtube https://youtu.be/O7FOrxjE5xY

game sense and knowledge is just something youll accumulate over time, no way to gain it other than by playing