I've just finished reading one of the best professional development books I've read (ever), and certainly the best one I've read this year. It's called The Wealthy Freelancer: 12 Secrets to a Great Income and an Enviable Lifestyle, and it's by Steve Slaunwhite, Pete Savage and Ed Gandia. Some of the information given is just good business practice, and things I'm already doing. Much more of the book is great ideas of things I haven't yet thought of, and hints on handling all the snags that will eventually come the way of a freelance writer. My list of action items I created for myself from reading this book will take me a while to complete, but promises to be helpful. I'd even recommend that book for most any self-employed entrepreneur, writer or not, because there are plenty of helpful tips on cultivating client relationships, marketing yourself and getting the most bang for your buck out of a host of things.
I'm a member of the Freelance Forum in Atlanta, a professional organization which has been invaluable to me these past few years as I've been on my own or preparing to me. I was away on a family vacation this summer when one authors of this book, Ed Gandia, was the speaker. I don't like to miss any of the Freelance Forum programming, but now that I've read The Wealthy Freelancer, I know I missed a great topic.
If you're freelancing and you haven't read this book, it comes with my highest recommendations.