That's a great question, ginger cat. The three principles you've laid out are good. So, I'd say you're on the right track in terms of strategy. What about tactic?
One thing I've learned as the organizer of a small Tendai group in a predominantly Christian area is that people come out of curiosity or some kind of felt need, but they only stay if they feel as though they belong. It doesn't matter so much if it's a Pure Land group, for instance, or any other kind of Buddhist practice (or yoga, or anything else really). So it makes sense to start with what we call "sangha building." Organize your meetings in such a way that people feel comfortable; give a period before meetings to orient new people and get to know them by name. Spend a period in practice. Afterward, as Andrew suggested, bring out the tea and biscuits and invite questions. Not necessarily about practice, but about anything at all. It shouldn't feel exclusive, that's the point. Once people feel like they belong, they have a motivation to learn more. Next thing, they're reading on their own and telling their friends...
How to help people find you? We've experimented with different approaches. Fliers were not very effective for us. People just sort of look past them. Advertisements in print media of various kinds didn't go much further. Word of mouth helps a lot (people telling people they know...). Online tools such as Facebook and Meetup do bring people to your door; I would recommend starting there.
I wish you great success!