Well, the trick is the follow through. You can tell it was a successfull kick if one of two things happen. When you hit the first head you're able to go through all 3 and all the puppies heads fly together, as if they're one. Or, if they look like those little desk toys where you let one hit the balls, then the far one jumps.
Really it's pretty easy and kicking puppies is a great confidence builder. I started a few years ago with Kittens but have since upgraded.
If you need any hints come join my forum,
www.puppykickers.com