At the risk of sounding like a bad Facebook meme, I'm trying to achieve total happiness in my life and have found that doing things like being happy with what I have (materialistic wise) and avoiding people who only bring me down or make me cross has really helped. Though the latter is bloody hard sometimes. I have some right wankers in my life. The former is surprisingly easy - I recently changed jobs from one where I was miserable to a lower paid one where I'm very happy. I have less disposable income but it doesn't bother me half as much as I thought it would as I'm not going to bed dreading the next day and wanting to spend 8 hours in tears.
So can I ask you lovely mumsnetters what your life hacks are for being happy and content!