Here are some exercises to heighten your sense of gratitude. They were written by my friend Vinita Wright and published in her book Days of Deepening Friendship.
Create a physical space in your life, in which you can focus on and enjoy creation. It could be a single potted plant or window box, a bird feeder, a window that gives a great view of the evening or morning sky. Try to involve all of your senses as you receive and appreciate what God has given you.
Go through a day—or through a single hour—and discipline yourself to attend to each moment as it comes and to note what is praiseworthy in that moment. Try to build this habit of dwelling completely in the moment at hand rather than in the past or future.
Identify some task you have accomplished and come up with a little celebration of it. This can be private or with friends.
Write a poem about one of your significant relationships. Make it a poem of wonder and praise.
Choose a natural process to enter more intentionally. You might try eating much more slowly and mindfully, thoroughly tasting the food. Or you could notice, over the next few nights, what your process is like for falling asleep. Allow yourself to enjoy the natural tension and release of ordinary processes in your life.