Only way I can do it is just take them flying. I got two folks interested and got them to start lessons but alas they never finished.
That's about all you can do though. I like to give people reasons to fly. For me, well I've always wanted to. I like to highlight camping trips, hunting (my dad took me moose hunting in Canada, part of the reason I want a single that can haul some weight), less traffic, faster to destination (seriously faster in longer distance trips), no groping pat-downs, et al.
You have to reach that part of a person that loves adventure, and learning too. Some people aren't into the learning though
For their spouses (if applicable) you have to highlight the safety of a small plane. You have to dispel that media induced scare that small planes fall like bricks, crash all the time, shatter like glass, et al.
FBO's could help too, but don't count on it. Most of them live by thin margins already. I wish they had rental "fleets" like car rental joints. Pick one up for a week for X price a day plus gas for something that will haul a family. Unfortunately, it's not feasible for most
Where pilots and FBO's could help is losing the elitist or cold attitude some project. Flying is fun, and should be friendly, jovial, et al. Unfortunately a small number act like c*cks.