I agree. What I do as a consulter is to make sure I do a good job (therefore I don't take any project if I don't think I'm a good fit) and then make sure that I stay in touch with my clients and some of their employees in the future. (having a lunch from time to time, or a coffee)

That's why I didn't have to actively search for clients in the last ten years. Employees switch jobs and remember me when their new employer has a project that fits my skill set.

They recommend me and I get the project. In most cases the project/position is never even advertised anywhere before I get it.