To be able to do a great ollie, I recommend learning how an ollie works. By this I mean how loading up on your back leg and releasing it gets you high up in the air. Learning how to ollie on a skateboard can and most likely will be extremely frustrating and time consuming. This is why I don't recommend it. Also, doing ollies when strapped to a board is a lot different than performing an ollie on a snowboard. I have some friends that can do 3 feet ollies on a skateboard and yet can't get a foot in the air when boarding. Anyways, you have to first learn how an ollie functions/works, and then you'll be that much closer to performing your first perfect ollie. The terrain you ride also plays a role in the ollie. You have to make yourself one with the terrain (Can't stop laughing after writing that). Anyways, you have to know when to ollie. It's hard to explain, but I'll give it a try. For optimal results when performing an ollie, you must execute it when the slope gives you a boost. You know when you're going super fast and sometimes you get some air without meaning to? You have to anticipate those moments and ollie right there. I really don't think this is helping you, but I gave it my best shot.