teaching beginners

I need some advice on how to teach someone to get up on the wakeboard who has no watersports experience at all. I'm used to teaching riders who are trying to learn their first inverts not trying to get out of the water, and it's been so long since I started boarding that I can't remember how I learned. I'm teaching people of different sizes and different natural athletic ability and most seem to be having the same problem: they all get pulled onto their faces. I don't mean that they're standing and then catching an edge. They go from sitting in the water waiting to go to basically rotating over the board forwards and face planting. I'm not gunning the throttle, so I know it's not a too much power issue. Any suggestions?