Throw the ball in front of yourself and practice catching to shoot.
The key thing is not bring the ball below waist height if you've already caught it at shoulder height (speed of shot).
Get the ball to your shoulder pocket as soon as possible.
Keep the ball even with the shoulders.
Do not wind up into the shot by catching the ball at shoulder height already in the pocket and then take the ball down to below waist level then lift it to the shooting position.
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.
The ball screen produces almost half of all professional offensive possessions, yet most teams still teach it as a memorised play. The modern approach trains the read - giving players a framework to decide based on what the defence does, not what the coach called.