Or at least cover your book. It doesn't have to be hard or expensive. But it should at least look professional, and more to the point, stop people in their tracks.
I came across an interesting study about what kind of pictures people like the best on Instagram. What does this have to do with book covers? Possibly everything. I think the study's results provide insight into creating covers that are eye-catching—and that is what you want, right? You want to grab people's attention. Make them pause and look at your book. As an example, take a look at this chart from the article:
Far more people prefer brighter photos to darker ones by a huge margin. Maybe your novel is really dark and perhaps you want your cover to reflect that. Or maybe what you really want is to make people stop and consider your book. Brighter could be better. Of course you shouldn't get too carried away with color as this chart shows:
Their next graph talks to the complexity of the cover, as exemplified by the number of edges in a picture:
This tells me that a cover that is too simple will not attract as much attention as a more complex one. Check out the source for more ideas that could improve your covers.