You sure should write fan fiction and likely already have—at least partly, in your head. When you think of how a character should have acted or what you wish had have happened instead, you’re essentially starting your own fanfic. This is a brand new world of ‘what ifs’ you get to explore. How far you want to explore that world is up to you.
In publishing, when your book gets presented to the editorial team as a real candidate for selling, your story will be reduced to a single page of to-the-point information known as the title information sheet. This piece of paper is the marketing pitch for your book, and contains important printing details the publisher will need to know for pricing reasons (among other things). So what goes into a title information sheet?