Decide on the type of book you want to write. Is it a work of fiction or nonfiction? Outline the project and work on it regularly. Try write 5 to 10 good pages a day. You'll be surprised how quickly the book comes together.
Edit the book thoroughly. Since you're self-publishing, you can't rely on an editorial team at a publishing house to look at it for you. The job falls on your shoulders. Don't rely on family and friends to give you an unbiased reading. Join a local writer's group if you can find one, and let other writers look at your manuscript. Consider taking it to a local college and paying an English literature or a creative writing teacher to read it critically. Now is a good time to register the manuscript with the United States Copyright Office (see Resources).
Design the cover for your book. You can contract an artist to do a cover for you. Advertise in the newspaper, advertise on Craigslist or consult a directory of freelance artists (see Resources). Negotiate the price and your usage rights for the artwork up-front. You should have rights to use the artwork in any way you see fit in conjunction with promoting your book.
Apply for an ISBN number for your book (see Resources). All printed books need to have one of these to be sold in retail markets. Fill out an application and provide basic information to get a unique number assigned to your book.
Take your manuscript and the cover art to a local printer who specializes in printing and binding books. Another option is to use a POD (print on demand) printer. There are many available online (see Resources). The advantage of a POD printer is that the books are printed as they're ordered, which means you don't have to print thousands of copies up-front and figure out how to store the books. Many POD printers print orders and ship them to customers for you as part of a package price.
Promote your book. Fill out an application to get Amazon.com to carry your book. Send free copies to writing websites that specialize in book reviews. Get your own website with your name as the domain name. Take advantage of the high visibility of the Internet to market yourself and your book. Contact local bookstores and offer to do a book signing. Anything you can do to get the word out about your book will improve sales.