People generally believe what they say themselves. Strangely, they don’t believe what YOU tell them nearly as often.
What implications does this have?
Perhaps you can illustrate the point you want to make with a powerful story, rather than provide the facts and the argument of the case. Perhaps you can give your colleagues or customers the same experience you had, that led you to your point of view? If you must provide rational argument, perhaps you can start it from what you know they already believe.
For example, rather than explaining your call center statistics, can you tell the story of Bob, who called to replace a defective product – can you describe what Bob said, what responses he received, how many times he was put on hold, for how long, and what music was playing in the background? Rather than describing the rationale for moving your offices from New York City to Poughkeepsie, can you relate the conversation you had about the relocation with your concerned spouse last night?
How can you help others say it, and believe it, for themselves? How can you do this while remaining genuine and not manipulative?