1) Don't look down, look about 6ft ahead
2) Power down with your arms, not up. You seem to be throwing them up, then letting them fall loosely by your side, this doesn't work. You need to move them up, then really slam them down.
3) Jump on your heels, not the entirety of your feet, and push really hard as you hit the floor. Keep your knees slightly bent, don't lock them, otherwise you'll kill all the bounce (and your back)
4) Stay the hell away from swimming pools