One of the most powerful methods of getting a message across is to tell a story.

Long testimonials in which the client tells their whole story are MUCH more powerful than an equal number of words in shorter testimonials.

Case histories / case studies that tell stories are a powerful way of communicating what you can do for the prospective client customer or patient.

If the story is about someone in a similar industry or with a similar problem to the prospect's, that's even better.