There's more than one way to skin a cat (whatever that means, yuck, don't worry Jack, I would never do that to you) and there are many ways to get your message out. Of course you will have to go do some research to find out what's available, and what suits your approach/agenda. Let's talk about the kinds of things you might find.
There are local, national and international directories that you could get listed in, of course reaching a different range of clientèle in each of them. There may be a local self-help organization or several) that publishes directories of self-help groups as a resource for local therapists and consumers. In Vancouver we have the well known 'Red Book', and the 'Self Help Resource also publishes a directory. Plus some directories may be oriented to a particular type of service, such as child-care, etc.
Your area may have a self-help or resource magazine/publication (or several) - consider the constituency or type of reader it reaches, will it include your prospective clients/members? Will you have to pay for advertising or can you agree to do a 'news item' or article with the publisher, perhaps on an ongoing basis? This may amount to free advertising for your group, especially if it's an arena the publisher wants to explore. If there's isn't one in your location, consider bringing one in from another city, and handling the distribution yourself. This is an easy sell to a publisher, and you may develop opportunities to be written-up. In addition, your geographic area needs representation in the magazine, and you may well be the group that establishes what that might be.
With advertising, you may have to maintain a consistent presence over a period of time before you see much response. You will help establish your credibility by being consistent and having a 'professional' look to the advertising you put out. What image do you want to have? This takes some thinking about, as well as proof-reading. One sloppy advertisement can label you as a bunch of… looney tunes? Let's not be too dysfunctional, shall we? Remember, you are trying to persuade someone to do something or respond or support you, or at least sympathise. Why should they bother to make the effort if you can't be bothered to proof-read your advertising? Psychology is a wonderful thing, but sometimes I just can't seem to get it out of my head…
Other peoples newsletters, I mean. There may be brother/sister organizations that work in the same area you do, and you might develop a working relationship whereby you can each promote your activities in the others newsletters and reach a larger joint audience together. Or you might even plan joint events, and share the costs and your resources; and have a better turn-out and greater success than you might have had alone.
Maybe there is a national, or umbrella organization/publication that can promote your events/agenda over a much wider area?
Any time you are in the public eye (event/advertising/articles), consider that this is a good-time to promote membership. Include membership and contact information on all your publications - bring membership forms or brochures, even your organization's business card to other peoples events, and especially your own.
I guess that means networking, and approaching people, finding out their interests and why they are here. Consider an official 'Greeter' at your events. Toastmasters does this to great effect. Everyone you talk to is a potential member, or at least someone willing to listen to your perspective, and who for a moment at least, sees things through your eyes. Winning political battles often (always?) starts with education. The hardest prison to break out of is the one where you can't see the bars, it's been said.
You may have some experienced and eloquent speakers in your organization. They could be excellent ambassadors for your organization. There are many groups that invite speakers to their meetings, some will pay an honorarium, some might even offer financial support in the form of a donation to your organization. But even if it's a 'freebie', taking the opportunity to address other groups helps you; your presence in the community is enhanced, your educational program moves forward, you win allies, and you open yourself to other's perspectives, and your own thought processes are sharpened in this environment for perhaps tougher political challenges or media opportunities that lie ahead. Don't forget to take newsletters, brochures and membership forms… But don't be too obvious. Try to work in a few quotes from Shakespeare; that always impresses people. Am I kidding? - I don't know anymore… Try to be sincere, but it's ok to fake it 'til you make it… But if you get caught, I didn't say anything…
Or, how to reach more people world-wide than you could ever talk to personally. But be careful, because they might send you e-mail (ask them for money first, and maybe they won't bother you). If you have an HTML guru, excellent. If not, wait 'til someone shows up who is. (Try praying). Or pay someone. Then if they are willing (to do it unpaid), and you care to pay for the space on someone's server to build your organizations web-page (for newsletters, manifestos, plans for world domination, chat lines etc.) and you are willing to tackle e-mail - go for it! But then you have to debate and draw up guidelines on what goes on the web-page and why, and what doesn't and why. Apparently it's the wave of the future, but personally I didn't get too excited about sliced white bread either (I have a gluten allergy). And I thought I was escaping computers when I quit my programming job, and here I am typing this in on my HOLIDAY! Self-help -that's supposed to be people oriented isn't it? Not technology, I've had too much technology - HELP! yourself, Felix. I hope someone appreciates this. Write to me c/o the institution on the front page, please, no e-mail. Nice warm touchy-feely paper - colours are nice too.