Amateur covers are obvious!
The number one mistake is made by adding all kinds of fancy trimmings to your type. Not only does it make the type much harder to read, but all trained designers have been strongly told that NO ONE EVER does that. As a result, there are very few professional covers with type stylized like that. If it is, the type is carefully embossed, maybe beveled. Using the minimal amount necessary to get the required effect. If the reader sees it, the quality reaction to the cover is compromised.
Click on the image above to see it full size. Look at how easy it is to read the top sample [when compared to the other two versions]. The middle one is actually very hard to read especially at the size of book pages on sites like Amazon, Lulu, Nook, Kobo, and the rest. But as you can see, even with careful embossing, the bottom example is also much more difficult to read.
The extra space between the T and i make even the top title quite bad. Always kern your titles.
The point is simple. If there are any compromises in readability with the full size artwork, by the time you downsample for the tiny online images, that artwork will not be readable at all. In fact, as you can see above, even the plain type on the top is difficult to read because all the thin places of the font disappear at this 100-pixel-wide version. You must be sure that you look at your cover designs in a small size to determine the readability of your design. It is absolutely crucial.
Readability is the goal of book typography
In a similar vein, we need to mention that lowercase is more than twice as readable as all caps. Plus, lowercase can be made much larger on a cover because lowercase is much shorter than all caps.
Finally, the readability of the font is very important. In the two examples above, both the top version [set in Buddy] and the bottom version [set in Contenu] as far easier to read than the original samples [set in Cutlass]. In fact, you should be able to see that Contenu is much more readable than Buddy. But color hurts these also.
Your name is important
In the same vein, your name needs to be very easy to read also. Your name is really your franchise. Your most recent book is simply a small addition to the platform.
Because all of our discovery is online, these things are crucial to our overall book design. None of it can be separated out. The cover, description, keywords, title, and so on are all equally important in the presentation of your book to your readers.
Don’t forget the complex background problem
The bad type issues we’ve just covered are usually severely exacerbated by the complex photos upon which the type is dumped. If the background has a lot of complex high contrast detail, your type does not stand a chance—even if it is a good font set well. White type will not be seen in front of the light or white portions of the photo just as black type will not be seen over the dark areas of a photo. An image which is constantly going back and forth ruins any hope of type readability.
There is no way to fix this problem except to get a better photo. You might place a light or dark rectangle behind the type, but that usually ruins the photo. Just imagine poor Gus [the Corgi] if his picture was reduced to a cover icon 100 pixels wide.
A lot of your sales decisions will be based on the professionalism of your cover—like it or not!
- The Importance of Designing for Readability (designshack.net) This article is good though compromised because it is written in Helvetica which is not very readable.