The most important part of the designer-client relationship is the relationship.
Put yourself into the shoes of the client. Why are they using you? Because you are “better” than the next? Hardly. It’s because there is less risk with you. They know what to expect when they put out $xxxx. They know it is easier to use you instead of going to something unknown. They know they won’t need to spend time getting the “new” guy up to speed. Their comfort with you is directly attributed to you having put in the time to create that relationship.
This is the reason why cold-calling rarely works. Sure you may hook someone by low-balling on price, but that relationship isn’t sustainable because they will dump you for the next low ball. Sometimes you get lucky and have a client coming out of a bad relationship and you can get them on the rebound. But that is pretty rare.
My firm was hit hard by the dot bomb and my boss was getting his most profitable business from the front-end research. So much so he didn’t want to design much. While I love the research part, I like doing the full monty of product development. I left and took all of the “design” clients with me.
And they left with me because of the relationship I created with them. There was no relationship with my boss.
Growing your client base is mostly by networking your relationships. You meet new people on new projects. People move from one company to another but they hold on to your relationship. I think the largest problem, at least for me, is the amount of work required to maintain that relationship. There is a lot of salesmanship involved. I prefer to spend my time on the nuts and bolts of product development.