There's a good piece on the Huffington Post called "10 Ways to Improve Depression and Anxiety without Meds." It's written by a psychiatrist, Dr Sheenie Ambardar, and I believe it is directed at an audience of people living with mood disorders. But I think it makes great advice for a general audience.
The first item on the list, "Limit Your Time on Facebook," cracked me up, but it is true. I think spending time on Facebook is okay if you're strategic about it, and do it for networking or professional purposes. Using your Facebook account as an extension of your personal life is another story.
I think the seventh item on the list, "Pick a Goal, Any Goal," is not specific enough. I can imagine somebody picking a huge task as a goal, and then getting anxious or depressed about not being able to achieve it. That would contradict the intentions of Dr Ambardar in writing the article.