I agree that covers or a hit or miss. When I'm making a cover, I try to make one that I know we'll appeal to potential readers. Often I'll use published book covers for inspiration.
For COT, I wanted to do something water related, but have the main character the center point of the cover. I also needed to add that element of a merman in there. It was hard with the 300 X 300 size limit.
Your covers aren't bad, but for the first cover, I don't get an idea of what the story is about. I like the second one, though.