The best way to propagate a Christmas cactus is to carefully cut off a section of a stem with at least one node (the point where the leaves join the stem). Make sure to use a clean, sharp knife or scissors to avoid damaging the plant. Gently remove any leaves or flowers that may be present on the stem. Then, allow the cut piece to dry for a few days before planting it in a well-draining soil mix. Keep the soil slightly moist, but not soggy, and keep the plant in a bright location with indirect sunlight. Water when the top inch of soil is dry.