For those of you that fear the RDP, I cannot stress enough that for every dive you do , you should plan it on the table, so by the time you get to your exams during your Divemaster course, its not such a mountain! Now with the introduction of the eRDPml its even more straight forward!
With physiology its always fun trying to remember all of your definitions, for the types of DCS, hypoxia etc I always draw people diagrams, labeling what effects where. Seems to help all my students too.
And always remember, the better understanding you have of the material through your divemaster, thats one thing less to worry about for your PADI IDC!