Use a mirror or window to look at your form and technique.
Whether it is passing, shooting or dribbling.
The feedback you get from seeing yourself is unbelievable. A lot of mistakes players make, they don't realise they are doing because it is a habit. The only way to change is to see what you are doing wrong.
Good team defence is five players guarding the ball, not five separate one-on-ones. The shell drill is where that starts, so here is how to teach help-side positioning and rotations from the first week of the season.
Rebounding is the least glamorous thing in basketball and one of the most decisive. It is also almost entirely a habit, which means it is entirely coachable.
Good spacing is only the start. The best modern offences teach players to attack the defence's rotations and play in a permanent 4-on-3 - here is how to coach that read.