To make a Christmas cactus bloom, provide it with the right balance of darkness, temperature, and care. Place the cactus in a cool spot (50-55°F) for at least 12 hours of darkness each day, starting around six weeks before you want it to bloom. Water sparingly, only when the soil feels dry, to avoid root rot. Gradually increase light and warmth once buds form. Use a balanced fertilizer monthly in spring and summer. Following these steps encourages vibrant blooms for the holiday season!