I am content.
I can say this truly and honestly, even with all of the problems I have in my life.
But being content has very little to do with your circumstances and everything to do with your attitude and the choices you make.
I am content because I choose to be.
Sometimes you're suddenly struck with an epiphany and you will forever remember your lesson. But most of the time you have to consciously remind yourself to follow what you know to be right. We have to remind ourselves to be polite, or to not be too hard on ourselves, or that winning isn't everything/the world is not a competition, and on and on.
This is something I have to do to be content and, even more than that, to be happy.
I have to remind myself how much better life feels when I'm happy, and remind myself that I always have a choice. I can choose to be happy, or I can choose to be sad or angry. While sometimes you may feel like you'd be happier getting upset or mopey, you'll remember that you're really just trying to be happy. If you're not convinced, think about which option you'd choose if you were feeling fine. Even just thinking of being happy can influence your mood for the positive.