Your voice is probably your strongest asset. Write or call your senator and representative. Write your local publication a letter to the editor outlining your views. (Regardless of your views, you can use this tool on the Organizing for America site to look up information about local newspapers.) Or join a group of like-minded advocates, such as the more than 11,000 doctors who delivered a petition outlining the points they think are critical to health care reform to Senate offices last Tuesday. As for Facebook: Nearly 1 million people updated their statuses to reflect their support of health care reform last Thursday. So while you're right that it may not be the most efficient avenue to change, you have to agree that the overwhelming number of your friends engaged in the issue made you think that maybe you should be, too. And that's the purpose of advocacy.
With your time, volunteer to educate others about reform, attend town-hall meetings or other public forums to discuss the issue, and help organize grassroots efforts to get out the "vote." And if you find an organization or politician you think is doing good work, consider supporting them with a donation.
Do you have a real-life do-gooding dilemma? Please send it to firstname.lastname@example.org and Sandy will try to answer it.