If you do some rules coverage I would say cover Fouls and Violations. Do a general coverage of all the Fouls and all the Violations that can be called (and their appropriate signals).

If you have more time, than you can go into a couple of the violations and the intricacies of them (travel...). Have your rule book handy and be able to find things quickly.

As for on court work - It may be useful to try and do a shadow program if you have games going on. Have an experienced ref talking in the ear of an unexperienced ref. They can help with position, where to watch, etc.

If you don't have games going on then cover positions, where to watch, communication (with your partner and the players).

Good luck.