The front and back covers should be 8 inches by 5.25 inches. The design will need to be rendered into the final CreateSpace ready template with spine after the contest, as the layout designer is requesting a cover before they can give a final page count.
The mood should be fun, and evoke a sense of excitement and mystery. I like designs that have characters in them, but only drawings or graphic designs, not pictures. If you choose to include characters, here are some quick descriptions; Kelsey, female protagonist: blonde hair, collarbone length, blue eyes, white. Gen, female protagonist: Latina, shoulder length very curly black hair, brown eyes. Isaac, male protagonist. Brown hair, curly on top with shaved sides. Hazel eyes, freckles. Fonts should be easy to read, but still have character. I attached a file of a book cover I like. Think like the original Harry Potter covers. I would prefer bright colors, but purple should be a motif, as well as clocks. The sign of one of the buildings in the book is a black, hanging metal sign with gold, cursive writing. If it makes sense, that could be a cool way to incorporate the title. The book takes place in New England over three time periods, 1811, 1952, and modern day, so feel free to play with those elements in your design. Finally, purple should be a central color, as it is a thematic element in the book. The blurb for the back cover should provide more clarification as to certain elements of the plot which may be pertinent. I also included the first chapter of the book, which you by no means have to read, but are welcome to if it would be helpful.