The goal of your footwork should be to get yourself in a position to take a normal swing at the ball as often as possible.
This means getting to the ball early enough so that you are making contact at the peak of the bounce and/or in between waist height and shoulder height whenever you can. If the ball gets below or above those areas, it is unlikely you will be able to use your normal swing and make the shot.
Practice turning shoulders and moving quickly at the beginning of your preparation, and slowing your feet down or getting set at the start of the swing.
These things will give you a much better chance of consistency and keep your contact point in a more comfortable position.
Steve Annacone, USPTA Elite Pro, is the Director of Annacone Tennis (http://www.annaconetennis.com). For details on lessons and camps at Sag Harbor Park Tennis and throughout the Hamptons this summer contact firstname.lastname@example.org or management@annaconetennis.