Chipping around the greens should be one of the easier parts of the game but I know it causes a lot of people major difficulties. I seem to find the pupils that struggle with their chipping have the ball position too far forward in their stance and their weight is incorrectly distributed between their feet (too much on their right side). From this position it makes it very difficult to strike the ball correctly.
You will more likely strike the ground before the ball or you will miss the ground and hit the ball thin. Inevitably this can lead to a jerky action or very active legs.
Stand with a narrow stance (heels approximately 5 inches apart). Position the ball just inside your right heel. Your weight should feel 70% on your left foot which will position your head more to the left of the ball. This gives you the chance to strike the ball first and then the ground.
Try to vary the clubs you use to chip with. Do not always use a sand wedge, try using a 9 or a 7 iron to create more of a chip and run shot where necessary. If you have green to play with, use it. Doing this will increase your margin for error and in turn improve your confidence.