Highly successful authors know where and what their Niche is

The 7 Traits of Highly Successful Authors

Trait #4: Highly successful authors know where and what their Niche is.
If there is ever a formula for failure, it’s the one that where the author believes, truly believes, that her book is for everyone. Nonsense. The more you niche yourself and your work, the more you “drill down” into that niche, the greater the success you have.

Books aren’t for everyone; knowing what your target market is enables you to write to them; to seek out their problems; to provide the entertainment that they seek; to provide the solutions they desire. Genders, generations and cultures look at situations from different perspectives. They seek solutions and receive information in different ways. They version of what’s humorous, dramatic or thrilling varies widely. No, you don’t write and publishing for the masses.
The mega millions of fans that the Harry Potter series enjoys has also mega millions of non-fans. The fans represent a population, as the non-fans do.

You need to find and know yours. It’s so much easier being the whale in the pond vs. the sardine in the sea.