Remove entire branches if necessary. Poor drainage, too frequent watering, or standing in water will cause root rot. Leaves will drop if soil is too wet or too dry. Dropping of older leaves and lower branches is natural. The foliage does very poorly on Norfolk Island Pines when handled, so try not to touch the branches and be sure the plant is not in a location where people or pets will brush against it frequently.
Seeds are available but can be difficult to germinate.