I have never been one to sound my own horn, but every expert tells me that I should include a Testimonials page. I was going to create a nice document rewritten with the clients and such, but decided instead to simply provide actual screen shots from my portfolio online. I have, of course, cropped these to exclude certain customer data that may be proprietary to the site I work from.
None-the-less, these should serve to show prospective clients the premium I place on quality writing.
Just remember, I guarantee all my work.
If I write for you, I guarantee your satisfaction with the piece. If I consult, you will learn. I have always and will always guaranteed my work. I believe that consulting should be no different.
You can always find writers and consultants that will place disclaimers on their work. I do not. If you want traffic on your site, see Jeff Folks. C. Jeff Oakes SEM Writing & Consulting.