Sell your e-book on Facebook.

if you were wise and wrote a book that caters to the audience you've been building up with your primary account, you've got a receptive, ready-made audience for your sales pitch.
Advertise it several times a day, both blatantly and at the end of other posts. Be creative and try to engage your readers. Get them excited about reading your book.
If you have other accounts (such as affiliate accounts), advertise your book there, too.
Always provide a link for reader to click to visit the page where they can purchase your book.

Get your e-book online. Createspace will post your book automatically. If you published it on your own computer, you can sell it a few different ways

Amazon will let you upload and sell your e-book as a Kindle book for free. (Kindle is the brand name of Amazon's popular e-reader product line.) This option is called Kindle Direct Publishing, or KDP.
On the plus side, KDP is fast and very flexible. You can publish your book in about 5 minutes, and set sale royalties for yourself as high as 70% (with Amazon taking the other 30%).
On the other hand, KDP does not publish your book for download outside of the Kindle marketplace. Readers who don't use Kindle won't be able to browse and purchase your book.
eBay will let you list items for sale at a set price. By offering a stock of “copies” of your e-book available for purchase on eBay, you can turn the venerable auction site into a de facto bookselling hub.
The advantage of eBay is its simplicity. Anyone with access to the site can potentially purchase a copy of your book – no special gadgets or software required.
The downside is the cost. eBay sets fees for just about everything; they only get worse when you set a fixed price point for purchases. Some of the fees are percentages, but others are flat, which can really bite into your profit margin if you're not careful.

Write an e-book.

Write an e-book. E-books are just book-format publications that are distributed electronically, rather than printed on paper. Because there's basically no cost to publish an e-book, pretty much anybody with an idea can do it.
Take it easy on yourself. Unlike a paper-and-ink book, your e-book doesn't have to be any particular number of pages. In fact, most e-books that are written to generate income are more like e-pamphlets than whole books.
Choose a subject that will generate interest. Nonfiction is almost always a better choice than fiction. Oddly enough, e-books that tell people how to make money selling e-books are a popular option, and they apparently sell enough to at least offset the trouble of writing them.
Write in an area where you can claim some kind of authority. It'll add cachet to your book. You don't need to show credentials, but you should write about something you're better at than the average Joe.