Since transitioning to work, but still keeping a notebook, I use the following. Colours based entirely on what pencils/highlighters I had when I first started taking notes at work.
Assigned work Blue
Ad hoc Orange
Errors Pink/Red
Solutions Green
Actualizing Yellow
WTF Purple
Math Green Science Blue History Yellow Writing RedSince transitioning to work, but still keeping a notebook, I use the following. Colours based entirely on what pencils/highlighters I had when I first started taking notes at work.