Its all basics, all of it be you recreational or elite. Whats the difference? Practice and attention.
Every paddler needs the same skills most of the time. To quote fight club you are not special, you are the same as every paddler.
So practice the basics in as many ways as you can. Same strokes different places.
That said a single rapid can prepare you for most things given a good mind. Sure there are things that cannot easily be practiced be it faster water, heavier water (more cubic metres aka pushier) and large drops, that said what you deal with these new things with will be the same strokes as used on a smaller familiar rapid. This smaller familiar rapid by its very nature of familiarity will allow you to relax and experiment. Then when you try harder/new rivers you can concentrate on the new features and not on the techniques themselves.
Practice the repertoire of your blade angles, balance, speed, direction of boat travel and play games and test oneself.
The article by the coach Dan John explains this in terms of physical training: