I found flashcards very useful when trying to memorize o-chem, but other than that I agree with the previous posters. I had the EK books, so I would read a whole section through, put anything really important on flashcards and try to understand anything else, and just hope the understanding was enough for the test. By and large it was, but there are a few things you need to have memorized, like the hormones. On the other hand, it's probably not important to memorize the digestive system in any great detail.