Drills
A deathmatch just for your crosshair
In one line: A deathmatch where your kill count does not matter, only where your crosshair sits while you move.
Goal
Get used to keeping your crosshair at head height and on the edge of corners, so that in duels you only have to click instead of moving your crosshair.
How to do it
Join a deathmatch and forget the score. While you move, watch only your crosshair: is it at head height? Is it on the edge an enemy can come out from? Every time you find it on the floor or in the middle of a wall, fix it and keep going.
Walk more often than you usually would: it is easier to control your crosshair when you are not running. When an enemy appears, notice whether your crosshair was already near their head or whether you had to move it a lot.
How you know it works
It works when your correction movements in duels get small: the enemy appears and your crosshair is already almost on the head. In the next deathmatch, try counting how many times you had to make a big vertical flick: it should keep going down.