[notsag-hn]

Cheatsheets are helpful when you already studied the thing, but not as your only source of info. The way I used to take notes at uni for example was to do it in layers. First, take a lot of notes, including your own impresions about what you're reading/writing/listening, be very verbose. Then start going through your notes and generate a summary of them. And then a summary of the summary over and over again until you get to something that is as short as a cheatsheet. This is indeed time-consuming but when you do have time it's very effective, at least it worked pretty well for me.