Gratitude is Learning to See
I've heard that making lists of things for which I should be grateful, and then thinking about these things, should in fact make me more grateful. Instead, I usually forget to make the lists, and when I do, it makes me feel like an ungrateful, entitled jerk for not feeling grateful. I've never found it helpful.
Gratitude is deeper than list-making. It is awareness of God in all things - awareness that all is grace and gift. Merton puts it well: "Gratitude is continually awakening to new wonder." In this way, gratitude is not about learning to write, but rather about learning to see.