Considering that this is a fantasy novel and the first of a five book series, I took this particular design approach where highlighting an important element of the story for each book. For this book I took Caleb's pocket watch and its magic. For the next book I could use Chelsea's fire magic elements, like so on. All the covers will then have 5 different elements of the story and will have 5 main different colors for each book. This way the covers would look simple and focused but not cluttered with elements at the same time.
I also wanted to give the title a magical feel as well while blending in to the surrounding.
For the back cover I placed a moon also since its another element of the story.