keeping a journal is helpful. it is therapeutic to vent negative emotions into a journal and gives you perspective when you read it again. also It gives you a feeling of posterity and immortality if you think that someone in the future might read what you wrote and possibly apply it to themselves. If nothing else, it feels cathartic to get thoughts down in an official way, on paper, in a complete and descriptive manner, and tends to put problems into perspective.

Master the skill of moderation. I don't think it's ever good to absolutely deny yourself something you enjoy, but it's worse to overindulge. Appreciating everything in life in small amounts promotes inner contentment and helps you relate to others because you're aware of what they enjoy firsthand.