I'm on similar thinking. Then, I got the idea of sticking tiny sticky notes where I wanted to write, which solved the problem. Write your notes in the stickies, then stick them with just a teeny-tiny piece protruding. Now, you can reference the notes and pick an area you thought was interesting by sticking a note on that page.

I just took a picture highlighting how I do now. Of course, room for improvement.

https://cdn.oinam.com/img/books/books-with-sticky-notes.jpg