The top ten list for improving happiness (found here via here)
1) Don't equate happiness with money. People adapt to income shifts relatively quickly, the long lasting benefits are essentially zero.
2) Exercise regularly. Regular exercise is an effective cure for mild depression and anxiety. It also stimulates more energy, and is good for the mind and body.
3) Have sex (preferably with someone you love). Need I say more?
4) Devote time and effort to close relationships. Confiding and discussing problems and issues is good for happiness, so work on these relationships.
5) Pause for reflection, meditate on the good things in life. Focusing on the good aspects of life helps to prevent hedonic adaptation.
6) Seek work that engages your skills, look to enjoy your job. Doing well at work creates happiness, and the easiest way of doing well at work, is doing a job you enjoy.
7) Give your body the sleep it needs. Too many people have a sleep deficit, resulting in fatigue, gloomy moods and lack of concentration.
8) Don't pursue happiness for its own sake, enjoy the moment. Because people don't understand what makes them happy, pursuing happiness can be self-defeating. Additionally, if people start to aim for happiness they are doing activities for happiness's sake rather than actually enjoying the activity itself.
9) Take control of your life, set yourself achievable goals. People are happiest when they achieve their aims, so set yourself goals which stretch you, but are achievable.
10) Remember to follow rules 1-9. Following these guidelines sounds easy, but actually requires willpower and effort.
To which I would add- spend some time in nature every day.