To propagate a Christmas cactus, you can use stem cuttings or leaf cuttings. First, choose a healthy stem or leaf that has a couple of nodes (the areas where the leaf and stem join). Cut it off and allow the cut end to dry out for a few days. Then, fill a small pot with soil and plant the cuttings. Water them regularly and keep them in a bright location, but not in direct sunlight. In a few weeks, the cuttings should start to sprout roots and grow.