In copywriting, I've often wondered if success was based solely on the results of your copy. It is hard to argue that it's not. For if your copy doesn't get results... or at least pay for itself... it's unlikely you'll be getting repeat business.
But may I suggest there may be something even more powerful than results...
That is RELATIONSHIP.
I've found that clients want to work with real people. People who can be themselves. People who work hard and produce results, but who aren't "business only."
In the past 5 months, I've begun to do some extra-ordinary things to cement client relationships. And you know what? It's working. My repeat business continues to grow.
I'm not going to share exactly what it is I'm doing because I don't want to be copied. Also, I'd rather you apply the principle and discover the tactics yourself. You'll gain more value from that anyway.
The core thing to remember as a copywriter is relationship. How do you further the relationship? What can you do so clients will want to do business with you again? (And in case I haven't made myself clear, the answer is not as simple as "get results.")