Getting yours to bloom for the Christmas season the following year can take some effort. Poinsettias need an equal or slightly greater amount of complete darkness vs light to bloom, just like Christmas Cactus and Thanksgiving Cactus. They require 12-14 hours of total darkness per day for 6-8 weeks to set color and produce flowers. When you start this depends on when you want it to bloom. The end of September to mid-October is generally the time to begin the process. You'll need to put it in a closet or place a large box over it every night for that prolonged darkness and then bring it back out or remove the box every morning for exposure to light. A room in your home that is dark for 12-14 hours, has windows, and isn’t used on a regular basis (like a guest room) would work also. You'll also want to cut back on regular watering.