How do you raise/maintain a poinsettia?

I have been a florist for over 25 years and every year I would have to care for over 100 Poinsettias. The one thing I have learned most is that any breeze, whether it be from the air vent or door opening will affect the plant. If the leaves that are wilting are turning black, this could be that it is getting a cold draft. If they are turning more brown, they may need to be watered a little more. With it getting the warm sun, it may be drying it out faster than you are watering it. The only time it will drop leaves from too much water is if it sits in water or is soggy. At which time the leaves would turn yellow. Just like most plants, they don't like to be moved around a lot. Good luck.