We all know that cramming isn't the most effective way of studying. The stress leading up to exams impacts how you store and recall information, meaning that you may remember words and phrases, but probably haven't forged the connections between different pieces of information and how they tie in together.
To give yourself the best chance of remembering details of cases in the exam, start now, before you're stressed and while you have time to form the requisite pathways in your brain.
This is a technique I learnt from a friend, which can be used to improve memory and retention when studying. This approach works best as a prompt for memory as you progress through the semester and means that (hopefully) by exam time you have saved most of the information you need in your long term memory and just need to recall and apply it.