Two effective techniques for influencing people are storytelling and using the Public Narrative tool from Marshall Ganz.
The best book we've read on storytelling is:
Lead with a Story (by Paul Smith)
Marshall Ganz has been an effective community organizer for many years, starting with the immigrant unionizing efforts in the California fruit fields. He developed a technique he called "Public Narrative" which is succinctly explained in this short PDF:
Public Narrative Participant Guide