Another learning trick (in ANY learning context, as far as I can see) is that you don't want to practice hour after hour. For instance, it's much better to do three half-hour practice sessions, at different times with other things intervening, than to practice for an hour and a half uninterruptedly. It appears that what you've gained by the short(er) practice period needs some time to sink in or something. Also, practicing when you've tired yourself out with practicing is less efficient.

Dave Oesterreich