Yeah, we're trying to teach you how to fish, not catch fish for you. Plus I think I butchered the hair slightly.
Jad's edit is solid gold and deserves some deconstruction. He has basically added two simple elements to the animation that are lacking in yours: anticipation and follow-through.

I have split the animation into its three parts. The first part is the anticipation or the windup. Anticipation is the visual clue that a counter-motion is about to begin. In this case it's the arm and fist moving behind the body, and the upper body shifting backwards to put more kinetic energy into the punch.
The second part is the delivery. This is short, only two frames, but it does its job of delivering the blow. Jad has used a nifty motion-blur effect to give it a greater sense of speed. You see this a lot in fighters.
The final part is the follow-through. The first frame of the follow-through is very similar to the last frame of the delivery. Our fighter guy had all this momentum pushing forward, so his fist can't instantly snap back. It needs to hang there for a second to transfer all its energy.

This is the same simple formula taken to greater extremes. Here the windup is bigger with more frames. He crouches down to build up more energy and keeps his kicking foot grounded all the way through the windup.
The delivery is again just two frames with a blur for effect. Here you can see one of Jad's tricks. He cut out the leg and shifted it forward a bit. This sets up the begining of the follow-through frames.
He leaves his leg out longer in the follow-through, again because a leg will generate much more momentum than a fist. Jad also adds a little hair moving effect to show that the character is returning to his neutral stance.