What aren’t you keeping track of when writing a book? You need to track pretty much everything you do to prepare to write your book. If you’re writing non-fiction, that seems to go without saying, because you want to oversee your research material (both to reference and for posterity), your bibliographical information (that you’ll include at the end of the book), any interviews that you conducted in your research, timelines, and so on.
Of course, you have to keep track of the facts if you’re writing a non-fiction book, but what do you need to track when you’re writing fiction? Honestly, you need to track the same things. But you also need to keep up with the things that you invent, not just the facts.
You definitely need character profiles, because you want characters to be consistent throughout the book. If you have a proper character from New York, using words such as ‘y’all’ and ‘ain’t,’ means something is not being tracked properly. You also probably want to know what is going on in your story before and as you write it, including getting an overall idea of where you want the story to go. As you write, you’ll want to avoid accidentally referencing something that you thought you included but you actually did not. It’s a good idea to write out a story timeline, as well as timelines for each of the major characters, especially if what they do when they aren’t in the direct narrative comes into play for their characters. You’ll want to keep track of the scenes, which characters are in them, and the settings.
When you write a story, make sure you know what is going on. It’s up to you, the author, to get the readers where they need to be, and to make sure that they know what’s happening as they are getting there. When you write non-fiction, it seems logical that you are keeping track of everything because you might need to verify your claims. In fiction, however, it is just as important to keep track of things, or you might get lost in your story.