While it may seem that you can browse for eBooks on Amazon, the truth is you can't - at least not in the same way you can a bookstore. Amazon "publish" every eBook that's approved for publication and that's an awful lot. At the time of writing, the Kindle Store reports just short of 1.7 million Kindle books or, for a more manageable figure, there are almost 42,000 science-fiction works. To put that in perspective I guess my local Waterstones has about 1,500 and that's probably being generous. You might think you can use filters to search for "good" books but even that's not reliable. Although you can search by rating, you can't specify how many ratings a book has to have so a search for "4 stars" or above will include works with only one reviewer, in many cases probably a friend or relative.
So, in short, if you have an eBook and you want to promote it, you're going to have to advertise.
"If I waited for perfection I would never write a word"
We get many enquiries on the Adwords Support Community asking questions about promoting eBooks and it's important to take the right approach. Many of the people who contact us are finding it difficult to get results - certainly profitable results - so you need to consider carefully how you approach the task.
Firstly you should become accustomed to the idea that advertising your book will be a loss-leader. It is highly unlikely you will see a short-term positive Return on Investment (ROI). Self-published eBooks are often quite inexpensive (especially when you consider the actual return from Amazon on a sale) and even with a half-decent conversion rate it's more than likely you will not see a profit from Adwords. I'm not saying it's impossible, but it's very unlikely so you need to understand and accept that. What you're doing with this advertising is trying to start the "snowball". At first you'll have few sales and you'll have to bear the cost of advertising but the idea is that this outlay gets the ball rolling so that in the future - providing the work is good and popular of course! - the income repays the original spend.
Next you'll need to think about where you advertise. Many authors seem to spend money on the Search network and I have to say I think this is a bad place to start. It's hard to imagine any keywords (for a fiction work) that would produce usable results. Even when considering a non-fiction work on a specific subject, Search may not be that useful without some keen work on establishing very tightly focused keywords. More importantly I think books need to be sold by their covers and this means Display Ads. Using an effective Image Ad on managed placements is far more likely to produce interested clicks. You can think of it as being like a promotion within a bookstore, something to catch the eye of someone browsing.
Note though, that it must be an effective image ad. Self-publishing does not mean you have to do it all yourself. If you're not a graphic designer and/or advertising professional, pay someone to make these Ads for you. Displaying a poorly made, amateur Display Ad is not going to be good for your campaign, it sends entirely the wrong impression. Image Ads don't have to be complex - you don't have to compete with Hollywood - but they need to look good and be enticing.
Don't forget the mobile market. Almost all eBooks will be read on mobile devices and while it used to be the Kindle, with very limited Internet capability, increasingly now people are using fully-featured tablets to read their books. Targeting mobile devices can allow you to include strong calls-to-action enticing the reader to download the book Now! and start reading.
Should you direct them to Amazon or your own website? I'd always recommend sending visitors to your own website initially, providing (lots of!) links to the Amazon page to complete the purchase. Your own site can promote the work still further - more images, more interesting (but short and punchy) description. You may even have a video trailer. Don't forget that Amazon have several ways to provide in-site links to products, make sure you choose a good selection and make use of customisation options to blend them well with your site design.
Again, as with the creatives themselves, don't try and build the website yourself if you're not a professional. Pay someone to do it for you, it'll be the best option in the long run.
If you do have a video trailer, consider Adwords for Video to place that trailer in front of the millions of YouTube viewers. Again, please don't even think of trying to make your own video. I've seen some and frankly I'd rather not think about any of them again.
Finally, don't sit back and relax, ever. It's true that once you get that snowball rolling there (hopefully) will be an element of inertia that'll see your sales increase over time. But this should also mean you'll be getting some disposable returns from those sales. Not much probably, but enough to plough back into more promotion, better Ad creatives, another video, etc. Don't give that snowball one push and watch it creep down the hill, keep pushing it, faster and faster until you can pay someone else to push it for you!