I started off with a traditional fantasy cover for Queen Mab (and anyone who purchases the ebook edition will have the original cover image as the first page). This was the image which hung over my desk as I wrote this book and inspired all the words that I put down on the page. I love this image by Howard David Johnson madly.
Unfortunately, most of my book sales are made on the internet, and when this image is reduced to the thumbnail size, the detail is lost. It is one of those things you have to think of when you switch your hat from "author" to "marketer".
So, I then switched the cover to a more icon themed cover, much like was found with Hunger Games or Game of Thrones.
This was a very trendy look in the fantasy world for awhile. It was designed by Damonza (who is considered one of the best bookcover designers out there). Most importantly, it fulfilled the need for "eye catching as a thumbnail".
Arresting, eye-catching, romantic and trendy... It was the perfect fit! Plus, it looks great in a thumbnail, too!
So if you are an author and your books are struggling, be willing to experiment. What defines a great cover changes and, fortunately, when you are both the CEO and peon of your own publishing empire, you have the flexibility to try to new things. And if the experiment fails? You pick up where you left off and continue the search.