Here is an idea that has worked well for me.
Okay, sounds dumb, but when your done look for an individual or couple that fits your target demographic and pay there tab (I use breakfast because it's usually cheap). They will usually be very surprised and try to talk you out of it, don't let them get away. After you pay (important), when they ask how they can thank you just hand them your card and ask them to stop by and visit sometime.
It doesn't always work, but a lot of people feel compelled to return the favor. Even if they don't, you can be sure you've made a favorable impression and they told at least one other person.