My advice for an aspiring writer is to research. Pull out your pen and note pad, and go to work. The more you can learn about the business of writing you will avoid the common mistakes first time author's make from lack of knowledge.
Also, WRITE EVERYDAY. Whether you feel like it or not. But most importantly READ. Read all kinds of books related to your preference. That way you can learn what you like and don't about writing styles and learn a trick or two from the bestsellers.