Kindle Store › Kindle eBooks › Fiction › Romance › Contemporary
It will need to compete against 27,710 other books, and will therefore need to be truly exceptional to stand out. However, if you list it under:
Kindle Store › Kindle eBooks › Fiction › Romance › Romantic Suspense
It will only have to compete against a much smaller 7,554 books, thus greatly increasing the chances it will sell.
The only problem is, the KDP system makes it nearly impossible to select the exact category you want your book to appear under since the category selection options do not correspond with the actual options listed in the Kindle Store. For my book, I was hoping to have it listed under these two small categories to maximize my chances of being read:
Kindle Store › Kindle eBooks › Fiction › Comic Fiction (93 books)
Kindle Store › Kindle eBooks › Humor › Comedy (663 books)
But these options do not exist in the category selection tool. I ended up choosing the closest I could find:
Fiction › Humorous
Humor › Topic › Relationships
When the book went up for publication, I found Amazon put it under the following categories:
Kindle Store › Kindle eBooks › Humor (31,441 books)
Books › Literature & Fiction › Women's Fiction › Single Women (20,054 books)
There is a way around this though. The KDP staff are happy to put your book in whatever category you wish, all you need to do is follow these steps:
1. Forget about selecting categories when you upload your book. Instead, scroll to the bottom of the category list and select NON-CLASSIFIABLE. (Had I known this was a required step, I would've saved myself some valuable time)
2. Once your book is listed for sale, go to the KDP dashboard. In the bottom right, select "Contact Us"
3. Under "What is the problem?" select "Editing Book Details" and type your request to have your categories changed.
4. Within 24 hours, KDP staff will reply and say they have manually added your book to the categories you requested.
(If you want to learn more about categories and why they are important, read M. Louisa's post)