Lots of food, lots of water - bamboo's are very greedy feeders and when grown in a pot will be dependent on you to supply them with everything. Consider re-potting into as large a size as you can manage too.

You can cut back culms (canes) that are completely dead and straw-coloured, but otherwise there's no need to cut the culms back, because they can and will sprout new foliage from the side shoots once they are happier.