I've written in notebooks for many years (mainly write-only, like perl). I think the key thing to remember is that no one is going to read or judge your notes,

I've written in notebooks for many years (mainly write-only, like perl). I think the key thing to remember is that no one is going to read or judge your notes, so literally write anything. Shopping lists, random thoughts, UML-like diagrams of code, sketches of possible art pieces, knots, etc. Just anything.