Not the easiest things to grow on but not impossible with a little care. Cut it back by 2/3 (being careful of the sap) and put it on a bright window sil away from cold draughts or warm radiators. Keep i on he dry side but don't let it dry out completely...don't over water either.
In April, pot it on into the next size pot. Don't go too big and still watch the watering. Keep it sprayed over to maintain humidity...once or twice a day is ok. In summer, a weekly liquid feed is good.
In autumn, to get the colour on the leaves, you will need to reduce the daylength by puting it in a dark cupboard for 14 hours a day.
Is it worth it? Probably not but it's a bit of fun. Poinsettias are tropical plants....i've seen them growing like weeds by he roadside in Barbados !!!