Facebook provides an excellent step by step guide on how to set up and 'operate' a Facebook 'business' page, which can be for a non-profit or a cause or even an event:
Creating a Facebook PAGE for your Business or Cause
There are numerous articles on how to use Twitter for non-profit causes.
Here's a Mashable article that reviews 25 of the top non-profits and their use of Twitter. Lots of examples of best practices from these large non-profits that can be 'scaled' to the local level for smaller organizations.
And here's an article with 11 tips for non-profits for how to optimize their use of Twitter. Among the key tips:
- Completely fill out your 'profile' to optimize search, and increase follow-backs
- Create and tweet content and links that will make "following" you worthwhile to your target audience (make it relevant, make it timely, make it interesting).
- Include click-through links
- Don't just promote your own links, retweet and share links from other org's
- Follow back everyone who follows you (then organize your followers with lists)
- Respond to people who engage with you
- Be conversational!