First you have to get your foot in the door and get somebody to listen with a somewhat open mind. You are working against a host of cognitive biases, e.g., confirmation bias, illusory correlation, Semmelweis bias*, subjective validation, availability cascade (repeat a lie often enough, etc.), bandwagon effect, conservatism bias (discounting the value of new information).
*Named after the doctor who discovered that the incidence of child bed fever infections could be dramatically reduced by doctors washing their hands. Nobody believed him and he was roundly condemned by the medical community. Eventually, he was confined against his will in a mental asylum, where he was severely beaten by guards and died not long afterward from, ironically, an infection.
And about 50 yrs after his find about handwashing, Dr. Lister proposed his radical theories about carbolic acid. Thank goodness, the medical world was slightly more prepared to listen at that point.
Andria