Keep the soil watered, but let the top two inches of soil dry out. Letting the soil become extremely dry will result in dry, and yellow, leaf drop. New green, leaves dropping off can be a sign of over watering. When this occurs the plant is in trouble, make sure it is using the water you give it.
These plants, when new, have a tendency to drop a noticeable amount of leaves. Don't panic, this is due to the trees being grown in ideal conditions, they are adjusting to your environment. The leaf loss may occur over several months. Pick up fallen leaves and remove yellow ones still on the plant. Cut off dead and dry twigs. This helps light to penetrate to the inside foliage, to promote growth on the inside.
Does it have adequate light?
Has it been moved in the past two or three weeks, therefore adjusting to a new light situation?
Did I let it dry out severely two weeks ago?
Did the air conditioner come on?
Did the heater come on?
Are the seasons changing?
Am I paying attention to the plant's use of water or am I just splashing water on it?
All the above questions have an effect on your ficus. They, like ourselves, do well where a consistent environment is possible. Common sense is a key factor to growing ficus, or any other plant.
There are several different varieties of ficus. The plants with similar looking leaves are ficus nitida, nuda, and a longer leafed variety is called alii.