Good points by Gary North on how to market yourself as an author and the basic steps of getting your first book in to print:
Book publishing is getting expensive. Profits are way down. Readership is declining for printed books.
Ebooks, yes. POD books, yes. But books published by a profit-seeking publisher are limited to low-risk authors. High-return authors are best.
If you have something to say, blog it. After a few years of blogging, write your first book. You will have an audience.
If your blog does not attract an audience, neither will your book. Publishers know this.
Bottom line: Start a blog and prove you can attract an audience… If you’ve got traffic, you are infinitely more likely to get your book published.
Gary’s full post is, So, You Want to Write Your First Book. Here Is How to Do It.