Folds and Cloth

Well it all comes down to force- fabric is under force from gravity of course, but the body makes force as it pushes the fabric or collects it (compressing). Look at your figures pose and identify where the body 'pokes' out of the fabric such as elbows and knees. Here the fabric is almost stretched looking so make straight short marks. Sometimes shoulders count as points as in the case of a sash, but most tailored clothing forms around the shoulder so there is no 'point'.
Usually where the body pokes it creates a collection point on the other side- again knees and elbows are good collection points as is the groin and armpit. For these I make slightly deeper indents.
Gravity only comes into play if the fabric is loose enough. When loose enough horizontal sections of cloth tend to sag at the middle- slightly if only a little loose, but sagging greatly when very loose (such as a skirt or robe).
I read a good many books about folds and drapery but to be honest it didnt tell me anything I didnt already know from simply observing the world around me- so go put on some baggy clothes and see how it bunches and hangs! :D
General Rules:
1. more folds mean loose cloth
2.sharp edged folds mean thick fabric, soft edged folds are a lighter fabric
Hair
Hair is done in a similar fashion as folds in cloth except hair tends to be in verticle waves. Place a blob of putty on the finished head and smooth it around into a rough approximation of the desired shape.
Gently push little waves and swirls down the length of the hair- try and create natural flowing lines as hair is rarely sharp or jagged. Do this across the whole of the head or until you complete the section of hair. By section I mean that sometimes I find that layering the hair with successive bits of putty also creates depth. My advice is to go and buy a fashion magazine and look at some of the hairstyles found within- most women have layered hairstyles.
For my folds I use clayshapers. I gently push the putty straight down or push it to one side when gathering folds. Because the rubber tip bends and applies pressure to the putty evenly the curves look natural. In the example of the wolf I started by pushing the putting gently downwards to create a layered look. I repeated this a few times to create a loose flowing look. Then i use one of my flat sharp edged tools to add the hairs texture.