I quickly noticed that the problem often comes from understanding the exercises given rather than the course itself, so here's how I like to proceed: I always start by first making sure that the principle of the course is understood by focusing on the points that block, and then we can start looking at the exercises, given by the teacher, that pose a problem. The goal is that at the end of the rehearsal course, the student has in his hands cards with the different methods used to solve all the possible types of exercises, especially those requested in the exam. I myself take care of preparing these sheets during the rehearsal course in order to summarize all the methods acquired.