What has been your most successful small town marketing technique?

Have you tried partnering up with another local business? Offer a class or session at their company for free for their employees. Then for those that are interested you can do a weekly session (mornings, lunch, evenings) for them. This works great for health facilities or doctor's offices. You can also try to do the same for teachers at any local schools. Word of mouth travels fast in small towns!

Word of mouth has really taken me far but, instructional demonstrations at local parks have worked really well too. They won't sign right then and there but they will talk about what they learn with the people they know and feel could benefit from their experience.

Statesboro, where I'm employed and where I go to school, is a pretty small place when you don't count the 20,000 plus student population (which is about to leave for winter break). I'm still very new at the gym, but I do understand what it's like to "do business" of any kind in a small town.

When I introduce myself to potential clients in the gym, I'm sure to make eye contact, smile, and give a good handshake. Those three things, especially, earn a lot of respect with the gym members here. More things are done with a handshake and verbal agreements than in most places. (That's not to say that we forego the contracts and whatnot, this isn't the wild west =P). People here tend to be more cautious. I'm not comfortable making a broad generalization by saying that's how it works in most small towns though.

I have a theory that the "getting to know you" phase is going to pay off once the gym members get more comfortable with me and the services that I can offer.

Stephen made a good point when he mentioned instructional demos. I've given out plenty of advice, and I've had those same people come up to me often and ask questions on form and things like that.

I participate in as many activities as I can in my small town
I am also an Ambassador to The Chamber of Commerce so I know what's going on
Get flyers out to as many places as you can
Post them at your local parks, cafes, schools, PTA's, hospitals, doctor and dental offices
Get a T shirt printed up and wear it everywhere!