The helix is a fairly simple move, once you figure it out. I'm gonna try to give you a step by step, and if after reading this all you do is crash, don't blame me. So here we go. We are going to assume that you're doing a helix starting on the left blade...
1. Get at the top of the pile/wave or wherever you're doing it. If it's a big wave, get one bounce going completely forward, if its a smaller wave move to step 2.
2. Initiate a bounce at 45 degrees, edging your boat slightly UPSTREAM, while leaning your body downstream. You basically want your front right edge to load up with a lot of energy. This will give you a lot of spinning momentum, and the momentum to flick the boat over your head. During all this you want your left blade to be in the water, controlling the angle of your bouncing and spin.
3. Now comes the tough part. Use your abs to flick the boat over your head, while keeping that spin going with the left blade. If the helix is aerial, you will have to shift the left stroke from a back stroke to a forward stroke. What you want to feel here is your edge releasing. The boat will suddenly feel really loose as you're getting up on the edge trying to get inverted. A common mistake that I see here is people getting all leaned back trying to flick the boat. don't do that, you'll look silly and nothing will happen. 90 percent of the time you will flick the boat over your head when you are perpindicular to the downstream current, not when you're facing upstream. Using that backwards left stroke is what gives you that 90 degree rotation.
4.As soon as you fell yourself upside down and backwards on the wave, roll up off your right blade. That rolling motion continues the inverted spin, and then you're up. You've just done a helix, now the ladies will flock to you and shower you with praise.
One final thing, don't get discouraged. When you feel that edge release for the first time, it will all make sense. You may not get it, but getting the edge release is deifinitely the hardest part.
Good luck
David