That was the question posed by Photshelter to about a dozen of the industry's top photogs.
Grover Sanschagrin compiled the best responses in his blog entry, "The Top 11 Things Photographers Wish They Learned in Photo School"
Here are the bare-bones bits of desired advice, but be sure to check out the blog yourself for the expanded commentary, which you will find invaluable.
11) How to treat others.What would you add to this list?
10) How to maintain a balanced life.
9) How to maintain an ethical standing in a changing photography business.
8) Where to find story ideas and things to photograph.
7) You don't have to be perfect.
6) How to keep your head up, navigate obstacles, and handle rejection.
5) How to continue to evolve and grow your career.
4) How to market myself, and my work.
3) It's not the camera, it's the photographer.
2) How to price their own work.
1) The realities of photography as a business.