In a recent post I asked the question “Are You Your Own Competition?”. I was pointing out (thanks to John Jantsch) that your actual competition may be the public’s perception that all law firms are alike. Accordingly, your real competition is your own failure to differentiate your firm from the pack.
I mention this again because Miriam Lawrence over at the Automatic Referrals blog (primarily for financial advisors) picked up on my post. She said:

“So in fact, you’re not really competing so much against other advisors as you are against your own inability to communicate your unique value.”(emphasis mine)

That’s what I was trying to say, but I just didn’t say it as well as Miriam. It really is more than differentiation, it is about your “unique value” in the eyes of prospective clients.
As part of your marketing, you need to get client feedback (as I have said to the point of ad nauseum some may say here, here, here, and here), and part of that should include asking your clients what they perceive your value as a law firm to be. That then should become the focus of your legal marketing message.