While swing changes should be a matter between yourself and your pro, there is one change I am going to recommend to you. It is one that you very likely need to make. Stop casting.
Casting is releasing your wrist set (the angle between the clubshaft and your left forearm, right forearm for lefties) just after you start the club back down from the top of your backswing. It looks like you’re casting a fishing line, hence the name. Do this, and you lose power and accuracy for no good reason.
Do you cast? Let’s find out. Swing up to the top of your backswing and look over your shoulder at the angle made by your forearm and the clubshaft. Set up again, swing the club up and then back down, stopping when your hands get hip high. Look at the angle your forearm and the clubshaft make now. Is it the same angle? If the forearm and shaft now make a straighter line than before, you’re casting.
The correct move is to retain your wrist set at least to that point until the speed of the swing builds up to where the set is naturally released and the club lashes into the ball.
Here’s an exercise. Swing up to the top at your usual speed, and swing back down slowly, very slowly, until your hands are hip high. Concentrate on maintaining that angle between your leading forearm and the club shaft. The way to do that is to turn your lower body and let your upper body follow at first without adding rotation of its own.
Slowly swing from hip level up to the top again and back down to hip level. Do this four times, and the fifth time, swinging at the same speed, swing through a finish, letting the wrists release.
The wrong way to stop casting is to hold onto the angle for dear life for as long as you can. That puts tension in your forearms, wrists, and hands. The wrists can’t release into the ball on time because they’re so locked up. Your ball striking will get worse, not better.
People do that when they try to get a “late hit.” There’s really no such thing as a late hit. Get that phrase out of your head. A relaxed swing with a retained wrist set delivers the hit on time.
In closing, let me repeat that the release of the wrists as they approach impact is a natural response to the momentum of the swing. It is not a deliberate act. It is not something you do. It is something that happens.