I have a dedicated couple of pages in a notebook, where I write down the note-taking conventions I use. When transitioning to a new notebook, I would copy those pages, possibly making a few improvements based on past usage. A most unhurried release cycle, if I can say so myself.

Regarding the space management, there are many solutions straight out of the programming world, of course: utilize both sides of the notebook, reserve a minimum number of pages per topic, keep an index with free pages, etc. But there are some hardware ones as well, I'm trying Atoma notebooks (https://atoma.be) these days.