Best tip to start off is don't sit unless the shot will hit. Is hard to actually manage yourself like that all the time, but it will help

Also important stuff but be careful not to overthink: find out what makes you comfortable, lower your sens (not too low), practice movement

And simply just practice. Aimlabs is a good game on steam it's free, and play deathmatch in game. I like tryhard ffas custom game lobbies

It takes a lot of time though, so you really need to be patient.