I asked my model to sit in loose fitting clothes on a chair in a position he was most comfortable with and I tried my best to stick to the brief for the exercise, that is to just concentrate on the outline of the clothes around the body, not worry too much about, head feet and hands and to then use lines and marks to indicate how the clothes sit around the body, giving a sense of the body within.
I found this quite straight forward as I seemed to get proportions right more or less first time and I didn’t have to worry about the detail of the more difficult features.
Please see my sketch below.
Deborah McAulay 