Push Ups: To most people, the difference between a push up on their knees and one from the toes seems huge and insurmountable. It isn't - you just need to understand techniques to assist your body in gaining the strength. Again we will focus on range of motion and the eccentric of the movement.
First, make sure you can do a proper push up from the knee postion. This means full range of motion, you need to be able to lower until your chest is almost on the floor. Rememeber chest to the floor, not chin! Do not reach forward and down with head and neck! If you can do this then the next step is to 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.