Many of my examinations in law were open book. This meant that we were allowed to bring any written materials at the examination venue. However, we were only given two hours and fifteen minutes to complete the examination. This meant that I had to organise my notes in a way that I will be able to retrieve them quickly.
This is not just to mark with sticky notes where topics are. This is also an aide memoir to prompt your mind of the main concepts and principles associated with a marker or label. For example, I used pink and red sticky markers for legislation and cases. I used blue and green for legal concepts and principles. I would also make a one-page summary of a chapter using diagrams and flowcharts. I would then mark that page with a special sticky marker with a different colour from the rest, for example, just a plain white sticky note.