Write stories tailored to a specific audience.
This can go two ways, especially fetish stories where you are writing to satisfy a certain kink.
For example, I have written some fat fetish material. Some readers with fetishes for fat girls aren't fussy, any story with overweight female characters is a good story to them. Others are quite particular in their fetish, and if your story doesn't fit to their specifics (for example the girl is overweight rather than obese and they like them bigger) they will lose interest very quickly.