My advice for young (and old) writers is the same I'd give to anybody trying to do anything - be yourself. Don't try to imitate. No one will ever be the next _______. Write a book, or create something that only you, and no one else can create. It's a great big sea of the same old shit out there, and the way to stand out is to be uniquely you - in a way no one else can be.
What does this entail? First, sticking to your own sensibilities. Obviously, people might disagree with your artistic choices, and even your editor might fight with you on this or that - but never let go of the things your gut tells you not to let go. Be yourself. Write your story, and no one else's. And by that I'm not saying to do something biographical. I mean to write characters the way YOU would write them, not how other people would write them.
Second, write books that you yourself would read. This is always how I have been when I compose music. I've alway sought to write/produce the music I wasn't hearing anywhere else, but wanted to hear, somewhere. Don't make what you think people would like, or try to be somebody else. Make what YOU like, and if you do it right, people will come along in time.
We all have greatness inside us. Sometimes we just don't know how to get it out or what to do with it. Again, you gotta be yourself. Whether you want to be a trackstar or a writer, you have to completely focus on that dream and WORK HARD. You can't play at things if you want to create something truly great.
Over the years I've seen a lot of artists abandon their work, as they grow up or have kids, or whatnot. And I realize while thinking back, few of them ever really worked at it anyway - they just played at art, and while some of them were quite talented, they didn't have that drive to really blow the roof off.
You have to care about what you're doing. I wouldn't describe my mother as your typical artist, but she is, in her own way. Her art is her garden, and she waters and prunes it and takes care of it every day. It is a wonderful site and experience to behold. But she doesn't play at it. She works at it, and that's how she makes something beautiful.
Anyway, I just wanted to give everyone a pep talk (me included).