Advise Appreciated

Ok now it is time to ask for some advice from my more experienced colleagues.

I met with a potential client today who absolutely needs to employ my services in order to be successful. The methodologies I advocate (leveraging social media for marketing and PR) are pretty new to the business world. There were two principles. The decision maker appeared to be stuck in the conventional, old-world model. The other 'gets it' but I suspect does not have enough influence to sway the decision-maker.

How do some of you convince a sceptical decision-maker that the revolutionary product or service you offer is not only key, but his only hope of success?

There are many great success stories, some of which I used today. Unfortunately, I don't have enough of my own success stories yet to carry the day solely based upon my own reputation.

Thanks in advance