To approach people about fortune telling, it helps to know what is called “the fortune teller’s paradox”. That, is, that people do not go to a fortune teller to have their future divined, but in the odd hope that the fortune teller can somehow *change* their future.
So for persons of faith, it helps to change their approach somewhat, to people who muck around with astrology, fortune telling and the like. Instead of pointing out the blindingly obvious that it doesn’t work, approach them from the point of view of helping someone to change their life for the better. This is something that faith *can* do, that fortune tellers cannot.
In short, they want personal change, so offer them personal change. Not directly from you, but to guide them to find and make change, with some heavenly help, in themselves.
Very excellant post.