A lot has been said and written about the importance of maintaining a stable core and lower half when making a full swing. In my experience, one of the reasons why players fail to maintain stability is weakness in their core which is magnified when there is a large amount of nervous energy in their bodies.
As anyone who has had problems with their pitching and chipping can tell you, nerves can get in the way very quickly!! If you suffer from problems with your chipping and pitching, ensure that you have a stable and supported lower body from the beginning to the end of the swing and you will find that the precision with which you can strike the ball will go up resulting in the nervous energy going down.
Get this feeling by gripping the legs to the floor at address and engaging your abdominal muscles and glutes. Keep your forearms and hands soft and begin your practice with short chip and run shots. Build to more advanced chips with a sandwedge maintaining the same stability in the lower half. If you can build to 40-50 yard pitch shots with the feet a little wider but solid and on the floor throughout to your finish, your short game will be on the right track.