Everything I Know about Self-Publishing by Kevin Kelly

You are expected to bring your audience.

So when an author today pitches a book to an established publisher, the second question from the publishers after “what is the book about” is “do you have an audience?” Because they don’t have an audience. They need the author and creators to bring their own audiences. So, the number of followers an author has, and how engaged they are, becomes central to whether the publisher will be interested in your project.

About promotion:

The short version: it is not hard to produce a book. It is much harder to find the audience for it and deliver the book to them. At least 50% of your energy will be devoted to selling the book. This is true whether you publish or self-publish.

The rule of thumb in publishing is that how well a book sells in its first two weeks determines whether it is a bestseller or not. You want to concentrate most of the sales as pre-sales – either on a crowdfunding platform, or on your own, or as pre-sales for a publisher. One way or another this promotion job will be your job, and can end up being at least half of your total effort on a book.