Commercial outlines are helpful as a guide, but the biggest benefit is the actual process of doing it yourself. Start as early as you can because your time becomes increasingly limited as the semester goes on. It may help to use your syllabus to start outlining the key concepts, and try not to go over 50 pages or it will become too cumbersome to actually use. I agree about the 1 - 2 page summery - that's very helpful. But in the end, do whatever works best for you. There's no single magical formula that works for everyone.