To appreciate what you have, develop your ability to form mental images. In the Pesach Haggadah, the Sages say we are obligated to view ourselves as having "once been slaves who have now gained freedom."

The more you are able to picture what life would be like if you were a slave and how elated you would feel on obtaining your freedom, the more grateful you will feel that you are presently free. As Pesach approaches, try to imagine that feeling.