Character biography. Now that you know who's who, here's a template for figuring out how they got to the situation in your novel. When it's time to write a flashback or refer to a past event, you'll breathe easier (and save yourself some edits) knowing you can look up the dates in this simple timeline.
A novel has a lot of moving parts. When you factor in research, articles saved with Web Clipper, and random jottings about who did what to whom, you'll probably find you have a lot of notes for your writing project. Consider adding a couple more to keep it all straight: a dashboard where you can manage the whole thing, and a checklist for bringing your completed opus to the world.