Author name is far larger than than the book title
Humans have great visual abilities, one of which is the ability to see objects that are different sizes and to quickly determine what is important without even thinking about it.
When we look at a sign, a newspaper page, a poster or a book cover, our eyes will usually go to the largest text first. In the case where a book cover is “busy” with a lot of design elements or an image that may distract the reader, large text is what gets read first.
Showing the author’s name in larger letters than the title can cause momentary confusion for the reader, especially if the reader is totally unfamiliar with the author.
If you want to promote your name, place it at the top of all your books and use the same typeface to create a consistent look, but make the book title larger than your name.
On the other hand, if you are an established author with several bestsellers, having your name at the top of the page and larger than the title may make sense.
“Lost” book title
If a book cover has an interesting landscape or action-packed cover image, it can be a challenge to place the title so that the title doesn’t cover part of the illustration or image.
I have seen many great cover images where the design places the book title into the image in such a way that the title seems like an afterthought. While placement of the title is a concern when designing a cover, the cover illustration or image alone is not what will turn a looker into a buyer.
It is perfectly acceptable to work text into an illustration or image, but it can be done in such a way that all the design elements of the cover work together.
Cover design is confusing or has too many elements
Cover elements are individual pieces of visual information that must be considered in order to understand the cover as a whole. The title is one element, the tagline is another, the author’s name is another element and so on.
Adding an image or illustration will introduce additional visual elements, as an image might have several people, and the people’s faces may have different expressions or there may other elements in the image such as a car, a building, the sun or moon.
When all cover elements are combined, a book cover design might have six to ten or more elements. A “busy” cover design is one in which many elements compete for attention and/or the reader must spend a lot of time looking and thinking about what they are seeing in order to fully understand the design.
Fewer elements will mean a simpler design that is more easily interpreted by the reader.
Use of inappropriate imagery
Inappropriate imagery can be a photograph or an artist’s illustration that has nothing to do with the book’s main characters or events. An image on the cover that shows a blonde woman prominently when the book describes her differently or has no such character would not be appropriate.
Another example of inappropriate imagery might be using PhotoShop to piece together several totally different images into one image that just doesn’t look real or seems unnatural.
Not considering online thumbnail images
When a book cover is designed for print, the book design can have very small type or use very subtle textures with the title and author’s name.
However, when the same cover design is shown at low resolutions on computers and tablets as a tiny thumbnail, formerly clear text becomes unreadable, or a richly textured cover may become blurry, as fine detail is lost when the image is reduced in size.
In some cases it may be necessary to have two versions of the cover: one for print, which is more detailed, and another version where the smaller text is enlarged or made a bit bolder so the text is more readable. However, when an image is reduced to less than 200 pixels wide, the smallest text on the cover simply won’t be rendered well, so make sure the title and author’s name are readable as thumbnails before publishing.