Publishers are attracted to you for exactly the same reasons that you are attractive to potential readers of your books. If, in the course of your work, you routinely engage with customers on a specific subject matter and you are perceived to be an expert, then you are attractive to that audience. If you have achieved a level of notoriety for an achievement, event, or record of accomplishment, then you have developed an audience that is attracted to you. If you have conducted extensive research and developed conclusions that can be life changing for a group of people, then you have the ability to attract an interested target audience.
All of these examples demonstrate the ability of an author to maintain a robust dialog with an interested audience and thereby to sell books on the subject matter. This helps the author to sell books, and it helps a publisher to decide whether to engage that author in their portfolio.
If you don’t have an existing relationship with a particular audience, will your book be a compelling read to a large group of people? Identify that group by its demographics, interests and any other way you can characterize them. Hint: The answer is not, ‘everyone’. Create a web site, along with a blog, facebook page, and twitter account. Even before you publish your book, begin posting content on your web site/blog/social media that is relevant to the subject matter of your book. Invite people to interact with you on the subject and begin building your audience.
If you are successful in generating a large number of followers online, you will have a ready-made audience for your book when it is published. Continue communicating your personal views along with other content you can provide to continue to maintain and build this interactive audience over time. Even after you publish your book, the role of the web site/bog/etc remains the same. You always want to build and maintain a subject-relevant relationship with your audience. Avoid the temptation to promote your book heavily on your site.
Some percentage of your followers will buy the book when they see it displayed on your site, or links to it on other mass distribution sites like Amazon.com or Kindle Reader. Regardless of how you choose to publish the book, learning and practicing the art of author attraction is the key to selling your book and to building a long term, loyal following.