In my experience, many of the students that have problems in chemistry are at least in part a result of merely memorizing the equations. This leads to easily being frustrated, which leads to a mental block. Then, the panic and time wasted blanking out on this question leads to a mental block on the next question on the test. I emphasize understanding the physical/chemical basis of the problem that they are trying to solve, so they are not relying completely on memorization. I also break up the problem into the following questions: Do I understand what am I being asked to solve? What are my knowns and unknowns? Based on this, what equation do I use? How do I solve the equation without a lot of calculator entries/re-entries/missed entries? There is always some memorization, but I put a greater emphasis on analysis and understanding the problem.