Start off with some speed...the key to pulling off a good sub it going just barely fast enough to where you thing, "hey...I think I may be going a little fast for this!". The ski should be on plane, and the water should be reasonably flat. Do a pre-hop, then do your setup hop. Your body position is pretty good in the pic, but you need to basically pull your feet up to your a**,while at the same time push down and lean forward on the handlepole. If you lean TOO far over the pole and chinpad, you'll end up going over the bars underwater-kinda fun, but not proper..lol. Essentially, you are aiming the nose of your ski into the water in front of you. The biggest part of the sub is speed, and rear lift. If you have those two things, the nose will end up dipping.