Aim practice

there's a lot of maps where u can train your aim

you can change the crosshair for most suitbable for you

The only thing to get better isn't the aim. But the tactics

Registrer and play faceit 1x1 or 2x2 competitions

A very important thing as well is to get comfortable with your mouse and movement with it, it sounds weird but after 5 years of using my mouse I just never got used to tracing or flicking with it until I started using Covac aim trainer, literally took me an hour of practice a day for 7 days and I've never been comfier with my mouse

i would recommend something like covakks thats the best for aim training all round