For instance, I just completed Phoenix in Shadow, sequel to Phoenix Rising, and the outline mostly went out the window pretty quickly. As I know that world so well, I didn't even use the outline once I started writing, except to look up names or something similar that I remembered inventing for the outline and didn't want to re-invent. But for the most part, I literally just let the characters lead me through their adventures until they reached the climactic points which I did know.
That latter bit is one of the crucial parts of writing for me. I absolutely must know what I'm heading for, and specifically I need to have in my mind some awesome, spectacular, and/or tearjerking scene that will serve as the climax of the story. I write towards that scene, as a goal. Everything within the story will be focused on serving that goal of reaching that climax, and making sure that every single piece needed to make that envisioned scene work will be there, precisely as required.
Terry Pratchett passed away recently - a victim of Alzheimer disease. That makes this article written at Bookseller more special. In it, Pratchett discusses the care and literal-and-figurative feeding of authors on tour.
It's a good idea to make sure advertising for the event takes place before the event. I wish I didn't have to say this.
Is there a table and chair? I wish I was joking, too. One shop once forgot these completely, and elsewhere I've sat on, at or around various strange items of bookshop furniture. It should be a real table and a real chair, not a stool in front of a shelf unit with no room for the knees. Try and put together something you would be comfortable sitting and writing at for several hours.
Give some thought to where the signing table is. I prefer to have my back to something - a wall, shelves, whatever. That means the kid with the blue anorak and one blocked nostril can't stare over my shoulder for two hours, which is off-putting (there's always one...)