The Strelitzia Nicolai is happiest when most of its soil is damp. Before watering, only let the top layer of soil dry out first. You can check this by dipping your finger about two inches into the soil. Aim to water your plant once a week- 10 days depending on the time of year. Please check the moisture levels before rewatering, if the top layer of soil is still moist, leave it a couple more days.
Your birds of paradise enjoy plenty of sunlight, so place it somewhere bright and sunny. Be careful of full sunshine in the heart of summer, as this could scorch the leaves and they may turn brown.
The Strelitzia will thrive in increased humidity, so try misting your plant in winter when the central heating is on and the air is dry.