The three steps to follow when organizing your notes to create a study guide are comparing notes, rewriting notes, synthesizing notes.
First of all, the best thing would be to take all of your notes (and perhaps those from your colleagues) and compare them to see if you missed something. Then, it is advisable to rewrite them so that everything is neat and organized, and easier to study from there. In the end, you synthesize all notes you and your colleagues wrote to create the ultimate notes.