This strategy has worked for me
What Greg describes here is exactly the way I've been able to make money as a consultant. People find me online because my resume shows up near the top of search results, and I have never paid a cent for SEO.
It helps to get good "intelligence" about rates and practices in your industry niche. That way you can show clients what a good deal they are getting with you. If you stick to your guns in negotiations you can pull off incredible contracts and still charge less than the big companies.
This is not to say that the process is easy. It mostly comes down to providing a desired service level. If you can provide a personal service to a client directly, that goes a long way. A survey done some years ago showed that the biggest complaint that large firms had about services/consulting firms had nothing to do with rates, but responsiveness. The big consulting firms aren't hungry enough. If a company knows that you will answer the phone and return messages then you can be as good as gold.
