What inspired you to write this book? Are the characters based off of people you know? where did you come up with the ideas? What was the most difficult part? What was the easiest part? What were things that you were going to put in the book but didn't and why? Hope that helped :)
Things you can ask an author: What's the best way to get rid of writer's block? Was it harder to write the serious parts or the humorous parts? Did you rewrite the book multiple times, or was it originally like this? Was getting published hard? What's the best method for developing characters? Does the book need to be only one genre? Did that help?