Everyone knows to pass out their link to Amazon to sell more books, although did you know that simply giving the root link isn’t enough?
The root link is the one Amazon gives you. It looks like this http://www.amazon.com/gp/product/B008GUMQHG
To help your ranking, you actually should do a search for your book using one of your key words. For example, my book here, my top key word (phrase) is ‘ebook cover design.’ So I typed that in Amazon’s search bar, scrolled through the books until I found mine, clicked on it to open the sales page, and I get a new link. This new link has lots of information in it, all mixed into the extra letters.
This is what it looks like now: http://www.amazon.com/Judge-Cover-Designing-Great-eBook-ebook/dp/B008GUMQHG/ref=sr_1_211?s=digital-text&ie=UTF8&qid=1446201433&sr=1-211&keywords=ebook+cover+design
Notice now it has some of the title of my book as well as the key phrase I used. I don’t like to hand out something so messy, so I take this over to bitly.com to shorten it. You can take their first option, which I like because it still says Amazon in the link, like this: http://amzn.to/1ScZLvm. Or you can customize it with your own words and you will get a link like this: http://bitly.com/book-cover.
Why, you ask, do you need to do this?
That long link actually tells Amazon that I was searching for a book on ebook cover design and that I found Judge a Book and opened it. That lets their system know that Judge a Book is indeed about ebook cover design. Each time someone uses this new link, it will look to Amazon as if they also did the search and find. More and more people using the link will help to raise the book up the ranks, above all the other books that didn’t get clicked on.