For The Millions, Hannah Gersen shares the visual aid she used to construct her novel and asks other writers about their own:

I got curious about the other visual aids that novelists create to manage their books, so I asked around and gathered a variety of notebook pages, diagrams, and timelines. In my search for material, I was often stymied by two factors: 1) writers had thrown out notes and materials related to finished novels and 2) writers were nervous about sharing their notes, especially for works-in-progress.