It gets scant watering in the winter and a good slosh once a week when the weather warms up. Too much water in early spring can be a cause of poor flowering in bougainvillea. When I say flowering I should point out that the flashy coloured bit is a bract, the flowers are far more staid, insignificant little trumpets held at the centre of each cluster of bracts. As for feeding, well it gets a couple of general purpose plant food slow release pellet shoved into the soil about now ish, that's it.
Since it is a fairly big plant (though it does not object to pruning) and a lover of good light the bougainvillea is probably best suited to life in a conservatory, but if you have the right spot it is very easy to keep. The rampant splash of colour this wonderfully undemanding plant is delivering is all the more welcome because outside it is grey, miserable and still raining!