Starting on your right side, hold yourself on your right elbow and feet on the ground. Be sure that your shoulders, hips and ankles are in a straight line. Do not let your shoulders slouch forward Start with 20 seconds and work your way up to a minute. Repeat on the other side.
For a slightly easier version, bend your knees and have your knees on the ground rather than your feet. This will shorten the lever, making the exercises a little easier until you can move up to the full version.