For me, writing is more a process of discovering the book than planning it.
I began my writing career in a very isolated place and time.
I've described my usual writing process as scrambling from peak to peak on inspiration through foggy valleys of despised logic. Inspiration is better when you can get it.
One of the best things about writing is how it redeems, not to mention recycles, all of one's prior experiences, including or perhaps especially the failures.
I've always tried to write the kind of book I most loved to read: character-centered adventure.