Specific answer to your question

Have a club trainer and buddy box available on Saturday's and Sundays. Put up a sign that offers free crashproof introductory flights.

When your club renews it's AMA charter also include your intro pilots in to the INTRO PILOT program. That facilitates the insurace coverage to the instructor and guest on the buddy box.

Limit the free flights to 3 total of 15 minutes or one tank of gass each. You will find folks that want to learn at your expense on your trainer. When it gets broke you are now fixing their errors.

If you see people standing around ask them if they want to try it.

About 20% of our members joined through being invited.