A golf punch shot is a really valuable shot to be able to execute when you need it.
A punch shot flies low, and if used effectively, can really help to lower your scores when you find yourself in a difficult position. Learning to hit a punch shot can really help in windy conditions as it will allow the ball to fly low, under the wind and therefore be less affected by the conditions, resulting in shots attacking the pin rather than being blown off target by the wind and ending up in a bunker or worse! Punch shots are also a great way of recovering from wayward shots ending up in the trees. Executing a good punch shot will allow you to recover from the trees and work the ball back into a good position with the yardage you achieve, rather than having to chip sideways and drop a shot because of this.
To hit a punch shot, set your feet at shoulder width apart but place the ball more towards your right foot than usual (for right handed golfers). Making sure you play the ball to the right of the centre of your stance will allow you to present the club head to the ball before it reaches the bottom of it's arc. This means that the club will be slightly de-lofted as it connects with the ball and this will produce a lower ball flight.
However, the key to achieving effective punch shots is learning to lead through the shot with your hands. All this means is that at set up, you should create a straight line from your left shoulder, through your left hand and down to the club head. As you look at the ball, your hands are now on the left of the ball in front of your left thigh and the club head is on the right of the ball. Your hands are leading the club head, your hands are more to the left than the club head is. As you swing away, maintain the straight line from your left shoulder, through your left hand and to the club head. You do not hinge your wrists if you want to keep the ball flight low. Swing to a maximum backswing position of waist height and then keep the straight line relationship of left shoulder, left hand and club head as you swing back down and through the ball. As you strike the ball your hands should be leading - meaning that they are more left than the club head. Look at the shaft angle at impact. The handle of the club is closer to the target than the club head is, resulting in the shaft of the club leaning over.
A great drill to practice for achieving this shaft angle so that the hands lead, is to get an impact bag and practice hitting the bag with the shaft of the club, rather than the club head, first. This encourages the correct leaning position for the club and allows the hands to stay on the left of the club head.
Your follow through position will be much lower than for a normal shot, with you stopping at waist height and again seeing that you have maintained the straight line from your left shoulder, through your left hand down to the club head.
Your right foot will also remain much lower to the floor than on a full shot, with your right heel just slightly lifting.