Having just recently been the recipient of an "I've just written the next Harry Potter" phone call, I must heartily concur with today's Editorial Anonymous post. Editorial Anonymous offers some terrific tips on determining your book's audience:

If I ask you if three-year-olds would like a book and you say "I don't know," what you're really saying is "I don't know what three-year-olds like." And that means that you don't get to write for them.

So be sure to read tons of children's books and get to know your audience, before you start writing your masterpiece.