A Facebook page is an essential tool for growing publicity for your campaign, building awareness of your issue, and conducting outreach with current and potential supporters. Set up a page so that people can "like" your campaign or organization. Include information about your campaign and a link to your official site in case people want more information.
Update your status a few times a week with recent developments or compelling information; the more people who like and share your status, the more publicity that status your campaign will get. Note that in general, photo and video updates tend to reach more people than text-only posts or links.
Facebook is particularly useful for coordinating events. You can create a page specifically for your event and use it as an electronic invitation, complete with details like a map to the event location, as well as the ability to easily update guests with last-minute changes. Share the event with your Facebook fans and encourage them to invite their friends.