Reps: "How many repetitions do I do?" I hear this all the time! You need to get stronger. Doing 10 to 15 reps on your knees and sacrificing form won't do it. Use as good a form as possible and do reps to failure (3- 5) and add a few more sets. If this is easy, then try: get in your push up position on your hands and knees with your arms straight.  Raise your knees and hold your body in a plank, lower your body until your chest is just off the floor, then gently place the knees on the floor and push back up. Try 3 to 5 of these or until failure.  If you can do this you'll be able to do a push up from the toes in no time. Once you can do one push up you may not be able to do two, so what do you do?  Use the lower on the toes push on the knees technique. Continue the progression until you can do multiple push ups in a row!