What you do after writing a book is publish it. It kind of gets put on hold for any writer or author whose book is still a work in progress because it has to happen after the actual writing process.

You do have an audience, regardless of what you write, and if you publish your book and market it well, people will read it.

But in the end, the book's quality will directly impact how well-received it is after it is published. Since writing is likely the most important aspect of publishing your first book, I doubt any writer would argue against highlighting the significance of this step in the process. This is the step that will probably require the greatest amount of effort, time, expertise, talent, inspiration, and editing.