Having attended many HIV/AIDS training courses, including by the mother of them all, the American Red Cross, I have realized that prevention is most effectively done one-on-one or in a small group —without lots of glitzy posters and other paraphernalia.
First, establish TRUST with the "students." Then begin by asking what they know about AIDS in general and what knowledge they have about prevention methods. At this point, do not start telling stories. This comes later, as a natural outcome of the session.
TRUST is the thing that makes this approach work: understanding the other person, how he/she thinks, what their native culture is and getting an idea of how open they are to receiving specific information. Wait until they are ready.
Today, as never before, there is a large pool of people who say they want to help. Go ahead—take them up on their offer. These individuals will be prepared, with some support, to be ambassadors for AIDS prevention with and among their peers.