Fiction writers dominate the top 100 in the Amazon store. If you don’t have a huge audience ready to buy your book, you can still succeed with other methods. Add the best keywords to your book (if you Self-publish). Pick relevant categories. Write a dynamite book description (and treat it like a sales page). Get on podcasts featuring fiction writers as guests. Guest post on blogs for fiction writers. Build a brand by telling readers the story behind the story. You can get attention if you build stages for it. Good luck!