Have you ever heard of bullet journaling? Its basic concept is simple: instead of using a day planner with formally assigned pre-printed pages, a bullet journal starts out completely blank. You assign pages in the front to be an index, and then write down important information and to-do lists as you go. Any time you want to dedicate space to a special subject (say ‘Plot Notes’) you can do so while just jotting down the page numbers of that topic back in the index. Its primary power lies in its versatility. It’s not just a day planner: it’s a to-list combined with a day planner plus a journal with a healthy dollop of idea book mixed together with…well…honestly anything you might want to write or draw.
There are, to misquote one of my favorite pirates, no rules with bullet journals, only guidelines.