Poinsettia will burn in direct sunlight so give your plant bright but indirect light. Try a west or south facing window. If your home environment is dry try adding some humidity. Also placing near other house plants will help.
Use a container that will drain well and if water collects in the tray so that the roots are not wet.
Water every 1-2 weeks allowing soil to dry out between watering. Do not place plants near heaters.
If you are experiencing leaf drop, the location of the plant may be too drafty or the plant may not be receiving enough water.