For my Book Design class this term, I had to design an entire book (it was awesome!) so here are the cover comps I came up with:
This first one had some nice elements, but it looked a bit old for the target audience of this book (middle-grade level readers).
I really liked this design as well, but it looks like an adult book.
This one was the clear favorite of my peers. It was by far the most age appropriate, and since it's a book for younger audiences, I could get away with having an image-based back cover. The author photo and bio is much more of an adult book element anyway.
Here's the final! I made some suggested improvements, like handlettering the text on the cover and adding the dragon's arms to hold the banner. I obviously redrew the front and back illustrations as well, and added some cracks around the dragon butt to add to the illusion of the dragon breaking through the back of the book cover. My classmates liked where the colors bled outside the lines in the comp, so I replicated that in the final. I moved the ISBN box to a more sensible place as well.
I had some trouble finding reference images for the dragon's butt, but as multiple people reminded me, dragons aren't real so I could draw it however I liked.