^ or just use training bots and ana bots.. without spending money xD or just practice and find your sensitivety and DPI and watch tutorials and videos to improve...
Just play a lot and find a decent setting that let's you do 180's without having to move your hand TOO far and so that the mouse isn't so fast that you over shoot your target all the time. It took me about 3 weeks to get used to the mouse and keyboard when I first started PC gaming with Quake.
It alla depends on you. I have my mouse arround 1400 dpi and the sensitivity at 15. I recommend using the dpi uou are comfortable with at the desktop and then change the ingame sensitivity
Aiming on pc is much easier. Youll get the hang of it if u keep practicing. Dont be surprised if when you go back to console it feels slow xD. Happened to me when my bf asked me to take over while he peed. The aiming was so hard for me.
DPI matters and mouse sensitivity settings in game. Also shut off any windows mouse assist settings like acceleration and that snap to feature. I use a mouse with 6 hotswap settings from 400 DPI for sniping up to 9000 DPI but mainly keep mine at 7000. Its all about adjustment from aim assist.
Large cloth mousepad, fairly decent brand (I have razer and logitech) for your mouse, dpi 400-1600 (800 is most common in the pros), low in game sense (like 8 or lower), do some warmups against bots.