Cover make make or break a book. Truth be told, a great cover gets us to glance at the book, pick it up and read the back copy (blurb) to see if it is for us.
Does it sound exciting?
Does the language pop?
Important questions. The same questions sound be asked of your cover.
Does it look exciting?
Does the image pop?
There are some shocking covers out there. Some are mine. LOL. But true.
I always believed a cover should preview what the book is about. Recently, I've discovered that's not exactly true. There are a lot of legacy published titles that have awesome covers that have nothing to do with the story (mostly, not always. For example: T. M. Logan's covers --so far-- match the story).
Let's look at a couple of examples: