Hit down on the ball in order to cause compression against the ground using the force of the irons club face. This creates backspin and loft, lifting the ball into the correct arc for the club chosen.
Mark your practice balls by placing a tee or coin an inch to the side of the ball. A correct iron swing will leave the divot just ahead of where the ball sat. If the divot is behind or at the ball, your shot is uncontrolled and low.
Keep your elbows straight and fight the urge to scoop the ball into the air with your wrists. By using the natural loft of the iron you have better control and a more desirable arc. The left hand should face the target at the point of contact with your right wrist bent gently away.
Shorten your follow through during practice to begin teaching the muscle memory required to gain consistency in your short irons game.
Stop the irons head when it gets below waist level. You'll find it is not possible to scoop the ball any longer if you are using the proper technique. Use a 5 iron while practicing this technique.
Use a full follow through on the course but you can always fall back to a shortened swing if you find yourself losing control of your iron shot.