Most people already know that you can make a push up more difficult by elevating the feet. Placing them on a chair works well for this. If you’re looking for the next step, ditch the chair, and find a wall to press your feet against.
Your feet shouldn’t be higher than knee height. Position yourself so that your body is about parallel to the ground in the starting position. Keep a slight bend in your knees, and play around with the hand positions a bit. In the bottom position, your chest should be between your hands, and your elbows should point back slightly. This exercise requires full body tension from the balls of your feet to your hands. Coordination is needed. Start by playing around with single or double reps. Make sure you’re warmed up. Enjoy!