If your Poinsettia was packaged in a plastic plant sleeve, take it off as soon as you get home so your plant is exposed to light and air.
Remove the foil wrapping that may be around the pot, as it impedes drainage and can cause your new Poinsettia to drown.
Place your plant in a bright location by a window. You can move it to the Christmas table whenever you want to display it, but the rest of the time, it likes a nice and well-lit spot.
Keep Poinsettias away from sources of heat or cold. It won’t like to be by the heater or fireplace, nor close to drafty windows.
Speaking of temperature, Poinsettias like it warm (but not hot) during the day and slightly cooler (around 60°F) at night. The warmer your house, the faster your Poinsettia flowers will open up—meaning a shorter bloom time.