Find happiness in the job you have NOW. Many people expect the right job or the right career to dramatically change their level of happiness, but happiness research makes it clear that your level of optimism and the quality of your relationships eclipse the satisfaction you gain from your job. If you have a positive outlook, you will make the best of any job, and if you have good relationships with people, you won't depend on your job to give your life a greater sense of meaning. You'll find it in your interactions with the people you care about. Now that doesn't mean you shouldn't aspire towards a job that will make you happier; it means you should understand that the capacity of your job to make you happy is quite small in comparison to your outlook on life and your relationships with people.
Personally, I think this is huge. I've known so very many people, actually, who think that finding just the right job will be the ultimate answer to whatever lack of fulfillment they are experiencing.
And here's another one I'll throw in free of charge! :-)
Smile. Science suggests that when you smile, whether you feel happy or not, your mood will be elevated. So smile all the time! In addition having enough money to pay the bills allows you to focus your energies on more productive aspects of your life, such a the pursuit of happiness as opposed to keeping the 'wolves from the door'.
It's not a bad little article, actually. You might like to click through and read the rest of it.