A common error when playing this shot is to hang back with a most of your weight on the back foot which produces a scooping action leading to both heavy and thin shots and no control over distance.
If this sounds familiar then try the following exercise on the range to get your weight moving correctly.
Address the ball with a golf ball under your right heel (right handed golfers) - see image below.

This will help you to get your right knee and clubhead working through the impact area together.
It requires a little work to get the sequencing right but you want to try and get the right knee and clubhead to work together from about the height you see in the next picture (see below).

This movement will help you strike the ball correctly and control the length you want to hit the ball. good luck and good golfing.
Tip courtesy of KeNako Golf & Sport Academy.