To propagate a Christmas cactus, take a short, Y-shaped cutting from the tip of the stem. Make sure the cutting has two to three jointed segments and that it comes from healthy, green foliage. Let the cutting dry for a few hours, then place it in a mixture of sandy soil and moist peat, covering about one-quarter of its length.
Put the pot in an area with bright but indirect light and water it sparingly to protect it from root rot. Allow it to root for two to three weeks before moving it to a larger pot. Water and feed it a bit more often than your established plant until it grows larger.