Desire is considered the opposite of contentment. If you are content, you don't desire anything. If you are discontent, you desire many things. The less content you are, the more you desire.
To use a current example from my own life, when I was making a very good income at Enron, I didn't have any interest in the state lottery. But after being unemployed for a few months, I started to fantasize constantly about winning the lottery. When I'm employed and earning a good income again, I probably won't think about the lottery again.
As my contentment decreases, my desire increases. But desire doesn't disappear when my needs are met. When I was making a good income, I also spent a lot of money and desired things I couldn't afford (such as a whitewater kayak).
So in order to increase my contentment, I would decrease my desires--in good times or bad. This, in fact, is the core of some religions (e.g. Buddhism) and philosophies (e.g. Taoism). One could say that the goal of a Christian, Muslim, or Jew is to seek contentment through a better relationship with God. Desiring only God would mean decreasing desire for other things, and being joyful about what God has provided the believer already. Spirituality is a means many people use worldwide in order to decrease their desires.
Besides spiritual avenues, there are other ways to decrease desire. Decreasing advertising is one. How many catalogs do you receive through the mail? How many ads do you see on TV or the Internet, or hear on the radio or by telephone? How much junk mail do you receive weekly? What steps can you take to decrease these advertisements?
Retreats from society can also decrease desire. Spend time in a forest, by a stream, near a mountain, or at a coast, as far from civilization as you can. Or, pray or meditate in silence, in a decluttered part of your home. Have coffee with a friend in a coffee shop where there are few distractions, just good conversation. Exercise. Listen to peaceful music. (I find that classical music is wonderful for decluttering my mind.) Avoid malls and online stores.
Feeling satiated helps tremendously. I said earlier how earning a good income made me uninterested in winning the lottery. Likewise, eating well keeps me uninterested in junk food and desserts most of the time. Pursuing dreams (and therefore desiring a clear head) reduces my hunger for mind-altering chemicals such as alcohol, sugar, caffeine, etc. Having a career I enjoy gives my life joy, so that I'm uninterested in buying a big house or fancy car.
Finally, taking advantage of what you have can keep you too busy to acquire anything more. Finish the books on your bookshelf (or at the library) before buying any more. Master an old hobby. List activities you used to do when you were younger, and choose one or two which don't cost much money. Stay in touch (or get in touch) with friends and family. Clean your home and mow your lawn so you will want to spend more time at home.
Religions preach a reduction in desire, but it's hard to get answers from them about how to actually reduce that desire. This article was an attempt to brainstorm several means of doing it, for my sake as well as that of my readers. I hope it inspired you. What can you do to increase spirituality, decrease advertising, retreat from society more often, feel satiated, or take advantage of what you have?