Although you may think that writing your book was the hard part, it's actually the book marketing process that takes guts, courage, blood, sweat and tears. Promoting your book is the next essential step in the process, particularly if you're a self-publisher, but even authors whose books have been published by big name publishers need to take their book's destiny into their hands and promote it to the public. Having your book listed on Amazon and Barnes & Noble is nice, but they won't do your book marketing for you.
You don't mention the subject matter of your book, so it's hard for me to give ideas on how to market it, but there are many ways to do so.
For a variety of ideas, one or two of which is sure to fit your style and comfort level in terms of interaction with the public, check out my articles on book promotion and book marketing. Even if you just start by writing and submitting a press release about your book, you'll get things rolling. The trick is to keep them rolling by keeping your book and your message in front of the public eye.