Stop trying to "convince" people.
You know, there is power in the testimony. A lot of startup companies use friends and family to test out the product and service and to help spread the word.
If there is any way to offer a trial of your service, you might give that a go as well.
Work to build several testimonies of folks who have worked with you and encourage them to tell others about what you are doing.
Do you have a website? Do you use facebook?
Those two areas would be good starters. A site would allow people to get better educated on what you offer, and facebook, in something like this, would be a good tool for word to travel around, especially, if people could put a video or two about their trip.