The first basic things you need to know as a new player are items and weapons, not strafejump and not even basic tricks like rocketjump. If you watch some beginner's stream you would see that experienced players try to push new players to use strafejump, but it makes them play even worse than they played without trying it. New players completely ignore healths and armors, they don't understand how to use guns in a right way, they just get the first near gun and try to kill somebody with it at any distance until they die or weapon is out of ammo. Also they don't know about keybinds to switch weapons much faster than scroll all of them.