Start trying to do them on a wakeskate. The landings aren't nearly as painful. It will let you learn technique, so when you strap on the wakeboard, you will already know the feeling when you are up there.
You have to look at the boat when you are in the air. Your body will follow your head.
Also, I cut all the way thru the wake. When I do it correctly (which I don't everytime), I get snapped back and then my feet come back underneath me.