What I do is I have an exercise book that I keep for each of the courses. I started this when I was in the middle of nowhere, with only limited internet access, like maybe once a week, and decided to learn the guitar, so I would write out notes for myself from each stage of the beginners course, draw chord diagrams or print them and paste them in, 3rd grade style.
This practice worked really well to help remember it, to summarize the important stuff, and to give me a place to make notes. And the books have proved to be invaluable resources to have around the flat.
It means of lot of fiddling around on the day you do a stage or whatever, but it has paid off, I think.
Although supporting this site is a worthy end in itself.