Indie publishers have limited resources for designing book covers and although Createspace has an easy to use book cover design wizard, you still need to have some idea of how you want your cover to look.
Up until now, my book covers have been simple, but a goal this year is to redesign them and make them more eye catching. I started collecting copies of book covers that I like to give me inspiration. Then I searched You Tube for "Mystery Book Cover Design." I'll be posting more on my progress, but meanwhile take a look at the video of Chip Kidd below (designer of the Jurassic Park book by Michael Crichton).
Tips from Book Cover Cafe
Authorhouse Cover Tips