I don't have a precise way of taking notes, and that's bad. I use a blank vscode page to lay out my thinking and sometimes I also re-write it on sticky notes or A4s from the printer. At the end of the day I have 10 sticky notes and 3-4 plain text files and to understand something you have to connect all the pieces lol.

Lately I've been eyeing some small digital whiteboards, they're super cheap on aliexpress but I can't comment on their quality (maybe non-existent)