I interviewed the authors of Detroit 2020, Jeff Conolly and Ben Daniels, at The Slaughtered Bird:
I would try to go way off the reservation, pitching Detroit 2020 video games and podcast plays. Ben would just smile and say, “That sounds great, but I think we should focus on chapter three.” So we’d write chapter three.
You have to find your fit to co-author well. My manic nature was perfect for drafting. I’d race ahead pumping out words faster than Ben would probably ever want to on his own. His more methodical nature was perfect for tidying behind me. With as fast as I move when I’m writing, I really struggle telling instead of showing. Ben kicked ass at really slowing down and giving the gory details. If you loved some gross, violent visual from the book, it’s likely that you have Ben to thank.
There’s a lot more; they clearly had a lot of fun answering the questions.