There are all kinds of techniques out there regarding chipping, pitching and sand shots. The most important swing thought is chest to chest.
The chest starts the swing and leads the swing. Begin by turning your chest away from the target then turn your chest toward the target. Allow the arms and hands to follow freely. At the highpoint of the back stroke your arms should still be moving backwards. Forcefully turn your chest toward the target and your arms will follow. As your arms begin to move forward your hands will fall behind the ball.
In order to direct the ball toward the target, point the right thumb toward the target. The ball will follow your right thumb.
Devil is in the details. At set up, put the ball on the toe of the club. Low shot, put the ball in the back of your stance. A pitch shot requires the ball to be in the middle of your stance. In order to create a high shot, the ball should be in front of your stance. On the follow through, allow the heel of your back foot to release and come up. This will assist you in pointing your chest toward the target.
Drill: Chip the ball 3 feet on to the green and allow the ball to roll the rest of the way to the hole. The further the hole is away the deeper in to your clubs you should go. For example, a 7 iron will roll the ball further than an 8 iron. A 9 iron will roll the ball further than a pitching wedge. Practice each shot using a backstroke no further than your ankles. Calibrate the different distances.