Be nice. (The world is a small town.)
You can’t be content with mastery; you have to push yourself to become a student again.
The minute you learn something, turn around and teach it to others.
Don't wait until you know who you are to get started.
The best advice is not to write what you know, it's to write what you like. Write the kind of story you like best - write the story you want to read. The same principle applies to your life and your career.
You are, in fact, a mashup of what you choose to let into your life. You are the sum of your influences. The German writer Goethe said, "We are shaped and fashioned by what we love."