Hey man, just start mentioning a few well based facts on
marijuana to your friends and eventually they might even mention it to someone else. Get a whole dominoes effect going. The only problem with my idea though is most stoners who talk about smoking pot is to other stoners cause the stoners who are speaking might be afraid the person might judge them differently, look down on them for some god know reason that was drilled into their minds when they were kids, or really won't give a hoot. :P I dunno.
Peace
Dirty Kid