The biggest mistake people make in growing Christmas cacti is treating them like a desert cactus. Instead treat them like a houseplant, with regular waterings. After they bloom, treat water less frequently watering until summer, when you go back to treating it like a houseplant. Also they don’t like direct sun. Instead find a bright spot away from direct sun. Also this is one plant that is quite comfortable being pot-bound for years. Regular fertilization is also helpful but be mindful that they are slow growers.
If your Christmas cactus has trouble blooming, you can help trigger blooms by doing one of the following: 1) Try setting it in your coolest room or near a cool window. This cool treatment will often trigger blooms. 2) Set your Christmas cactus in a room where you never turn on the lights at night– perhaps a guest room? Uninterrupted periods of darkness this time of year will often encourage blooms.