One of the coolest shots you can hit in golf is the towering long iron. There’s a great drill I have called “halfway back; all the way through” that will give you a fuller finish. A real killer for some of these long irons is a steep attack angle and abbreviated follow-through, which translates into your shots.
The drill is very simple: swing the club half the way back and all the way through, holding that finish until the ball lands. This will give you an idea of the speed and the tempo you need to get all the way to the finish, and that is what makes for a good mid-to-long iron.