I can't remember who mentioned this in a previous response post, but someone said that some designers go full force with keeping within the genre's typical design elements while others incorporate only a few of those elements. As a result, their designs become more timeless than the very cliche designs. This made me think a lot about keeping that in mind when I design. So kudos!
Here is an example of Sci-fi books:
Notice the similarity in font choice too. Below are a couple of links. One is an awesome infographic on NPR's sci-fi and fantasy picks. The other is a helpful website about color meaning. I wish there were a website with color palettes and their meaning. But then maybe that would be too easy.
Infograpahic
Symbolism
