Forbes has a great list of "20 Things 2o Year-Olds Don't Get." Here's an excerpt:
Don’t Wait to Be Told What to Do – You can’t have a sense of entitlement without a sense of responsibility. You’ll never get ahead by waiting for someone to tell you what to do. Saying “nobody asked me to do this” is a guaranteed recipe for failure. Err on the side of doing too much, not too little. (Watch: Millennials in the Workplace Training Video)
Take Responsibility for Your Mistakes – You should be making lots of mistakes when you’re early on in your career. But you shouldn’t be defensive about errors in judgment or execution. Stop trying to justify your F-ups. You’re only going to grow by embracing the lessons learned from your mistakes, and committing to learn from those experiences.
You Should Be Getting Your Butt Kicked – Meryl Streep in “The Devil Wears Prada” would be the most valuable boss you could possibly have. This is the most impressionable, malleable and formative stage of your professional career. Working for someone that demands excellence and pushes your limits every day will build the most solid foundation for your ongoing professional success.