Poinsettias like their soil to dry out a little between watering. This means don’t water your poinsettia every day. Maybe once a week, depending on how dry your climate is.
Most poinsettias come with their pots wrapped in decorative foil. Leaving your poinsettia in the foil will not allow the pot to drain completely, so remove your poinsettia from the foil as soon as possible. Your poinsettia shouldn’t sit in standing water. Make sure the pot is able to drain, and that the drip pan dries out, or empty it.
Poinsettias are very sensitive to cold air and direct sunlight.
I put my old poinsettia outside a few times. The evenings in Monterey get pretty cold sometimes, so my poor poinsettia got a little stressed by being outside.
I left my poinsettia out on the front porch on a rather sunny day (thinking it would do it some good) and ended up burning most of the leaves on my beautiful poinsettia! So, keep your poinsettia safe and guard it from direct sunlight!
Keep your poinsettia warm. It thrives in temperatures between 68-70 degrees F.
Hopefully this will get you started.
Source: Paul Ecke Ranch website