It’s hard to overstate this one. You’d think it would be obvious, until you see how many people don’t follow it. When you do something you know you’re good at, that you are totally immersed in, in flows confidence, self-esteem, enjoyment, passion, positivity and all the other things that bring happiness.

Even if you can’t find work doing something that excites you, you can still make sure that you do your job well. Even in a tedious-but-it-pays-the-bills kind of a job, there’s a world of difference between going through the motions and doing it really well. If you have to be there, for goodness’ sake make sure you’re the best you can be at the job, if only because you’ll be far happier if you do. (Best of all, do that while formulating a plan to move on to something else more fulfilling.)

And whether or not you currently have the job you’d choose, what about all the things you do with the rest of your time? Whether it’s a hobby, or cooking for the family, or voluntary work, or sport, do something you can lose yourself in, that gives you a real sense of achievement.

Please note that I’m not saying you should never do anything you’re not good at. Even a concert pianist must once have been not good at the piano. We’d never learn if we couldn’t start anything we weren’t already good at. And some things have to be done and will never be our forte. In my case, for example, cleaning the house. But be conscious that in order to be happy you need to spend as much time as you reasonably can doing things that you can be proud of.

When you know you’re doing a thing well, you get into a rhythm that is really therapeutic. Whether you’re wowing an audience with a presentation, swimming like an otter, turning your child’s fear to confidence, creating a photograph of the sunset that looks better than the real thing, helping a patient to feel comfortable and relaxed, or baking a cake the family will have devoured before it’s even cold, that sense of being lost in something that flows smoothly because you know exactly what you’re doing is one of the most beguiling feelings there is. For many of us, it’s when we’re at our happiest. So obviously the more we can find that feeling, the more often we’ll be happy. And since happiness is largely a matter of habit, we’ll get into the habit of feeling good about ourselves more and more.