slow and steady. build a good base, meaning work on riding heel and toe edges, from one side of the boat to the other first, then start trying to jump, again practice both heel and toe. on new tricks start small, go back to 17-18 mph and practice going from inside the wake to outside and land the trick 3x before going wake to wake with it. I am just regurgitating everything from the detention dvd.
I've broke a few bones wake boarding and snowboarding and the nerves rattle when trying new tricks, but I just go back to baby steps to bring the confidence back, or I do a shot of tequila and pray mid-air to the lake god's not to snap me like a twig.
BUT, wake boarding should be fun, don't kill the mood by forcing yourself to learn something every single set. doing the basics you are good at will help also just be building muscle memory/strength. however, those sets I tell myself 'I won't try anything new this time and just have fun' end up being the set I land a new trick on.