Note taking methodologies for dense CS textbooks

Hey Beehaw!

I've recently received a copy of Physically Based Rendering 4th edition. I've been going through the book slowly, but have had a hard time retaining information. I used to use markdown to take extensive notes, but found that I would end up copying too much useless information. Also, writing latex notes for math is painfully slow.

I was wondering what note taking methodologies you all use. I think my ideal note taking method would fulfill three criteria:

1. Minimal note-taking overhead: Doesn't take too much time to create notes. (Esp for complex math expressions)
2. Easy to reference: The notes should be brief and easy to comprehend at a glance. They should also be searchable.
3. Easy to store: Minimal physical presence. I tend to lose papers all the time.