Some tips:
Anatomically speaking female breast consists of two things: firm muscular base + soft upper tissue (fat).
To draw them correctly you have to remember two things: what’s the age of your model and what’s the physical condition of it.
Younger = more round, fresh, hard. Muscles are in good shape, that shoulder – chest line is pretty clear and overall form of the breast has a good tension and volume in it.
Older: muscles are more stretched, gravity took its tall on that soft tissue part. Overall shape is more like a wheel running down the hill.
Here are some references:


