On iron shots, hit the ball with the back of your left hand facing the target. Your hands will lead the clubhead, so the shaft is angled slightly toward the target at impact (above, left). This allows you to drive the club down and through the shot and take a divot after the ball. It also ensures that you hit from the inside for power and produce a penetrating flight.
Don't try to roll your hands over at impact (above, right). With the club going 90 miles an hour, your brain doesn't have time to tell your hands to do that with any accuracy. You can see here my hands have rolled too much, causing the clubface to shut and the shaft to tilt away from the target, which makes it hard to hit the ball solid. I'll bet this one went low and left.
Most shanks come from too much right hand and arm on the downswing. The result is an out-to-in swing path and a clubface so closed at impact that the hosel has moved out toward the ball. A lot of golfers think the shank comes from the face being open--because the ball goes to the right--so they try to close the face more. Result: more shanks. Here's a drill that can break the cycle. Place a headcover just outside the toe of your wedge at address, and practice hitting balls without touching the head-cover (see photo). You won't close the clubface, and you'll approach from the inside.