They really should have a class on this which is a 9-credit class, funded by the department (and not your adviser who wants you to work on research projects on his or her dime), in which all you do is prepare for the RPE! Heck, it could even be an independent study with your adviser (in fact probably should be), because you inevitably end up being rushed and not doing a good job. The result? Well the exam that is supposed to tech you your area ends up wasting yours and your adviser's time, cause severe sleep depravation, and not really teach you anything of substance!
But, alas, I still have to study for it!