You find your writing voice by being an avid reader. Read all kinds of books, fiction, non-fiction, books you might not normally choose off of a shelf. It is all research and learning. What kind of stories really speak to you, humor, drama - know what you like and learn how you want to "sound" in your writing. And then write write write, every day a little something. It is like a video game in a sense, the more you play, the better you get. Writing is like that.