If you are just starting out and have little or no fan base, then you need to think of creative ways to build one.
One thing I like to do is incorporate public domain characters into my story.
This means taking a famous character from the public domain and reimagining them in my story.
So for example, Snow White is a public domain character, therefor I can write a story where she is a central character. There are also recent movies about her so she is very popular at the moment.
There a plenty of famous characters that are now in the public domain, a quick google search will tell you everything you need to know.
While it is okay to use a character from the public domain, that doesn't mean you can copy a story that they have appeared in. If you were to write a book that basically copies another book with a public domain character then you would be breaching copyright.