discoveringdavinci:

“You ought not to give to drapery a great confusion of many folds, but rather only introduce them where they are held by the hands or the arms; the rest you may let fall simply where it is its nature to flow; and do not let the nude forms be broken by too many details and interrupted folds. 

How draperies should be drawn from nature: that is to say if you want to represent woolen cloth draw the folds from that; and if it is to be silk, or fine cloth or coarse  or of linen or of crepe, vary the folds in each and do not represent dresses, as many do, from models covered with paper or thin leather which will deceive you greatly. - Leonardo da Vinci