I write in the same genre, but I don't sell enough to consider myself a good mentor on the marketing side. But I can offer these basic tips which may help:
1) Share an Amazon link to your book in the appropriate subforum. People here can help evaluate the blurb, cover and sample to see if they're genre appropriate and enticing.
2) Share what you're doing to actively market the book. (If the answer is nothing, then that could be your answer: your book isn't visible, therefore no one has an opportunity to buy it.)
3) Take a step back and consider you may be asking this question too early. In general, single books relying on passive marketing don't sell. That's the norm, even for books that may be "good". Also, actively marketing a single book can be highly difficult to make profitable, even if it gets books selling. So common wisdom is to get at least three books in a series published and some active marketing running before drawing conclusions about how well they're selling.