Hi Matt,
I'm currently reading several books by the author Joanna Penn. She writes self-help books and nonfiction about how to make a living as a writer.
She says in most of her books (I'm paraphrasing here): know your goals. Do you want to write a book for the sake of having a book? Or do you want commercial success? There are two different strategies for each.
Personally, I'm choosing commercial success as my goal! :)
Cheers,
Amy