When I think of an audience, I think of an auditorium filled with people. Um ... that's not how it works when you're trying to build an audience of readers. Often, you have to find them one at a time. That's not easy to do, especially in these days of being an Indie Author, where you have no powerhouse of a publisher behind you. (Although I know plenty of authors who will say their NY publishers did zippity-do-dah to get word of their books out there.)
The best way to find readers has always been through word of mouth. But how does one do that?
Well, you have to find people who are willing to talk about the books and stories they read.