demo review, play mge, play lobbies/whatever pugs u can find, try ur hardest in scrims

movement modes like jump/surf/bhop are all great, especially considering jump is pretty accessable even for offline gaming

to go one step further spending a good amount of time on maps alone either jumping around on soldier, looking for and practicing trap spots on demo, and practicing movement for entering/exiting points on medic and scout are also really good ways to gain redundant levels of familiarity with maps and allow you to make some tasks almost automatic

this kind of thing can be tedious but has helped me in the past, especially when it comes to trying to learn new maps or maps that have had significant alterations to them

You could try aim trainers/kovaaks. I've personally felt that they help me on scout, but I don't think that they would help as much for the projectile classes.

this.

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

I've never seen anyone ever suggest this, and it does seem kind of counterintuitive, but you can always just play other FPS with similar physics to improve/relax from tf2.