Coloured notes: definitely. One training course I went on, I don't even remember what it was about; the only thing I took away from it was a new note-taking technique (I hadn't heard of 'mind mapping' before). I started taking notes at the meetings in coloured texter, and eventually a code formed. Red or black generally indicated an especially obtuse line of argument.
Mum found my notebooks a few months ago and showed them to me as 'proof' of how convinced I used to be. I opened them up, they were almost all red and black. I couldn't tell her what that meant....