Neil Gaiman gave the Commencement Address to the University of the Arts in Philadelphia. Neil explained the subject of his address as "Everything I could think of that someone starting out on a career in the arts right now might need to know."
It's a fantastic speech for writers. He talks about the lessons he learned over the years, how he learned to write and reveals the best advice he ever received (it was from Stephen King and he immediately ignored it).
Neil had some specific advice for freelances of all kinds:
I will pass on some secret freelancer knowledge. Secret knowledge is always good. And it is useful for anyone who ever plans to create art for other people, to enter a freelance world of any kind. I learned it in comics, but it applies to other fields too. And it's this:
You get work however you get work, but keep people keep working in a freelance world (and more and more of today's world is freelance), because their work is good, because they are easy to get along with and because they deliver the work on time. And you don't even need all three! Two out of three is fine. People will tolerate how unpleasant you are if your work is good and you deliver it on time. People will forgive the lateness of your work if it is good and they like you. And you don't have to be as good as everyone else if you're on time and it's always a pleasure to hear from you.
Here's the speech in full:
You can read the transcript of Neil's excellent address here