Definately don't do the bounce thing. That just teaches you to ollie wrong. Do what Mark said: Build some tension, but then flatten the board back out, then ollie, then let go with trailing hand. All in rapid succession.
With that said... Learning ollie 180's is cool and all, but even some of the pros do them waaaaay too much. Learn some stuff switch off the wake instead of having to do a 180 after every 180 or 540.