As far as getting full power from a punch, technique can definately help. But once you get the feel for putting your body into a punch and hitting with full power, the main thing technique will help with is defense and throwing combos.

So lets take number 3 for example. The twist in your "put out the cigarette motion" and turn in your hips and shoulders is where your power will come from.

If you push of a little with the twist, then thats only to get a step closer to land the punch.

Your power comes from your legs, hips and body.

When you use "the put out a cig" twist with your feet this is to allow you to turn your hips and shoulders into the punch.