https://www.youtube.com/watch?v=OfxUckgFLoc

This applies to every shooter. Focused practice. Pick a thing you want to work on and then work on that thing and don't worry about winning. Things I do every warm up:
180 degree turns: when you run in a straight line, turn 180 degrees, run backwards, turn 180 degrees, run forward. Make sure your crosshair stays at head level and you don't over or undershoot your turns.
aiming: practice tracing and flicking separately. You can practice tracing by trying to keep your crosshair on a teammates head if there are no enemies around. pratice flick shots by choosing random targets in the environment and flick to them. jiggle peaking is also a thing in almost any shooter. eliminate angles you can get attacked from using walls and obstacles. Peek, shoot, and get back to cover. Learn the environment. Visualize the terrain that's hidden by an obstacles and when you peek, be aware of the difference of your mental image and the environment.

Most recent "gaming" mice have good sensors in them these days, but there's a chance you have a really shitty sensor that makes your life harder than it should be. If you find you can't do 180° turns accurately, it might be your mouse sensor and not muscle memory.
In terms of sensitivity: the lowest sens that you can still do 180 turns with comfortably is what you should aim for. Most people play way too high sens for their own good.