Water correctly
Poinsettias should neither become completely soaked nor dried out, although too much water is worse than a temporary lack of it. You can determine whether it’s time to water with a finger test. If the soil feels dry to a depth of about 2cm, the plant needs water. Another way to determine this is to lift the plant along with its pot. If it feels unusually light, the soil lacks moisture. Depending on the location, ambient temperature and size of the plant, you may need to water daily or every two to three days. Water with water at room temperature. You can do this in small amounts using a watering can from above, or from below by pouring water into the water tray. Another method is the immersion technique, in which the root ball is completely immersed in room temperature water for a few minutes. Afterwards, allow it to drain well. With the last method, watering once a week is usually enough. When using any of the three methods, make sure the water doesn't sit in the tray or planter for a long time. Pour off any excess no later than 15 minutes after watering.
No need to fertilise during the first flowering
When you buy a poinsettia in November or December, the soil is already pre-fertilised, meaning it's not necessary to fertilise your plant during the flowering period. Only if you decide to continue growing your poinsettia are regular applications of fertiliser advisable.
Should you make it bloom again?
Theoretically, it's possible to get a poinsettia to bloom again, however, this requires a lot of effort and the plant rarely looks as impressive as it did in the first year. But even if you don't want to make your plant flower again, you don't have to get rid of it. After pruning at the end of the flowering period, poinsettias turn into lush green plants that do very well outdoors in the warmer months.