How does everyone prepare for writing a longer piece, i.e. a novel?
I typically spend a painstaking amount of time outlining my world and its characters first. I write down all sorts of details I feel like I may not ever truly write about, as I feel like it really helps my world come alive. I have loads of documents detailing everything from politics to locales to design elements of the different areas of my world.
When I'm done, I then outline my entire story, chapter by chapter, in what often ends up being anywhere between a 20,000-40,000 word document. I treat it like small, but detailed summaries for each chapter, so by the time I finally begin writing my first draft, it already has the feel and quality of something I've already completely written out and edited. I like my first draft to be as detailed and professional feeling as possible, as I find it makes the editing process later much easier.