...people don't make buying decisions based on what's good for you--they act based on what they see, need and believe.He's not speaking specifically to lawyers, but he might as well be: clients will gladly pay you exactly what they think you've earned. It's up to you to make sure that number is in the right range.
Read the post. Then focus on building and maintaining the trust of your clients, on ensuring that your work product matches your reputation, on providing meaningful value in every representation. On establishing "long-term trust," as Godin calls it. Whatever you call it, it's the key to getting paid what you deserve.