Have to agree with Pamela, here. Breaking through that initial trust barrier is best done in person.

A couple of ways might come to mind.
If you have worked with people in the past, and you know them in a different context from your work (for example, family or friends), you could ask them to tell you in their own words what difference you made to them. That would be valuable testimonial material.

Also, you could share some valuable information about posture, lifting or some other common trigger event you come across in your business. Share it with a local networking group, or an arthritis or orthopaedic forum.

Be helpful, build authority (especially locally), and make it so that when people do meet you, they feel they already know you.