Watch some videos on wakeboarding Ollie's or wake skate, the motion is the same you actually push hard down with your rear foot and the board will pop and push you up. It's more a timing thing, get a gopro or camera and record all your sets then review. That's the fastest way to improve.
http://www.instgram.com/jlyons30
2002 Moomba Mobius LSV - Sold
2006 Moomba Mobius LSV - Sold
2017 Moomba Craz - Enzos, Lead