How did you plan the last novel you wrote (and successfully finished)? Outline? Synopsis? Summary? Divination Rod? Nuthin' at all?
Nuthin' at all.
I had the back cover blurb for
Eve of Chaos that I'd submitted several months before (and had coverflats for already), but that was it. I knew I had to wrap up plot threads from previous books in the series, so I scratched them down on a scrap piece of paper to check off as I went, but I had no outline, synop, etc. They're useless to me because the final book will bear no resemblance to that early "guess" of what I'm going to write about. New avenues pop up as I go, and they're always better than whatever I thought of before.
Writing, for me, is an adventure. I never know how the story is going to end until I get there.