Something big happened when the Kindle became popular. Suddenly, it wasn’t just important that your cover image look amazing in real life. You also needed to have a great cover that worked as a teeny tiny thumbnail image. Don’t believe me? Find a book on Amazon and look at the cover images under “Customers Who Bought This Item Also Bought.”

What you should see is a sea of good and bad covers. What makes them stand out? Do any of them catch your eye? Why? You’ll probably notice a few things about the standouts:

• Big, readable text
• Clear imagery—big pictures that are obvious what they are
• Eye-catching colors

You don’t have to have all of those to stand out, but even just one helps. But how do you tell that your cover is working amidst a sea of others?

If you have a book on Amazon, head on down to the “Customers Who Bought This Item Also Bought” section and pick one of the books in there. Chances are your book will be in that section on that title. For example, here’s Finding the Core of Your Story in that section:

And so you can see that this still holds true for fiction titles, here’s one of the related books sections on Amazon with a couple books by my friend Katie Daniels. Her cover for Fire and Ashes stands out especially well.

Wait! This is only any good if your book is already on Amazon, right? How do you discover if your cover works in a thumbnail without putting it up for sale first? Well, I’ll tell you.

Go to Amazon’s page for the category your book will be listed in. Click a few of the top ones and then scroll down to the section with the recommended related books. Save a bunch of those thumbnail covers to your computer, then take your cover and scale it down to the same size. Make a graphic like this one:

Can you find my book? More importantly, can you find your book in your own version of this graphic? If not, seriously consider thinking of ways to make it stand out better. Because whether you like it or not, the book-selling world is now highly dependent on how good you can look from a distance.