This addresses what seems to be a Catch-22 for a lot of writers at various career stages: the current need to be semi-famous in your field to help an agent sell the book. The author has to bring ever more to the table in the way of a waiting audience.
This book is the best thinking I've seen on the subject of how to do it. And it's aimed at both fiction and nonfiction, extrovert and introvert. You don't have to be techie to understand it. And it doesn't make me feel bad, as some experts do, that I haven't done all the suggested things already.
Author Christina Katz, also known as Writer Mama, has been "Empowering Writers Since 1998."
You'll likely be hearing more about this book from me. Or maybe you'll just see the dazzling results.