Re: Any good ideas?
You could put together a series of smaller packages, say a 5 hour taster, a 10 hour "Master the hover square" and so on. It'll break things up into smaller more digestible chunks and allow people who maybe don't want to go the whole hog to come away with something. Some people want more than a half hour trial lesson, but won't be too keen on the costs of a full PPL. You'll have 5 hours to change their minds. Others will go away happy having hovered the beast, with no further ambitions. Again you'll have plenty of time to change their minds. Make sure you point out that all the hours count, if they do decide to continue.
It may be worth taking a stall to the local farm/country shows, or just turn up at them, talk, hand out leaflets, talk, stress how useful a helicopter could be to a landowner, try and get people who've never even thought about aviation to come to your school and have a look.
And vitally, as tangovictor pointed out, treat your students or potential students as people. Friendly, informal, underpinned by a sense of professionalism is the atmosphere to aim for. Anyone walks through the door looking a bit lost, sling a coffee and chocolate Hob Nob in their hands and chat.