In the bad old days of publishing, it was extremely difficult to get a publisher, or even an agent, unless you had what is called a "Platform," that is, a group of people who would most likely buy your book.
Celebrities, even those who couldn't spell their own name, could get a book deal. Millions of people knew and loved them. They had a platform.
People who did a lot of public speaking, with a long mailing list, had a platform.
Today, in the good new days of Indie publishing, you still need a platform. Not to publish, but to sell. It's so much easier to get published, but there are so many more titles competing for attention.
The difference today is you can BUILD a platform. Social media are free. Blogs are free (in most cases). You can promote your book through your own Facebook, Twitter, Pinterest and other accounts. You can also promote it on other people's blogs and internet radio shows. You can approach online book reviewers.
Plus, you can still pitch your book to the traditional media. Jack Canfield and Mark Victor Hansen have sold over 157 million Chicken Soup books so far. They give much of the credit to their willingness to be guests on hundreds of radio shows, no matter how small the audience.
All it takes to get in the traditional media (and much of the online media) is a good press release and time. By the way, as a former journalist, I know from experience that you must have a press release if you want the media to take you seriously. (See the previous post on having a Media Page)
You might need to hire someone to guide you through the maze and/or do the work for you, especially if time is an issue. But you must, I repeat, must, build your platform. No book, no matter how good it is,will automatically sell itself. People have to know about it.
It's easy to get discouraged if you don't see immediate results. In most cases, people need to be exposed to a marketing message from seven to 16 times before they buy. So, no matter what happens, or doesn't happen, continue to build your platform. Eventually, you will create a critical mass of awareness. If your book is any good, it WILL start selling. People who buy your book will tell their friends. Word-of-mouth marketing is the most powerful selling tool you can have. But to get it, you must build your platform.