wow, I really love that naked sketch...you should make a naked version as well!
it really shows you are a great artist, but you dont have any clue how to do folds.
Basically it goes like this.
1 -Know the shapes of the clothing articles, what bends and what doesnt, what's tight and what's loose.
2 -imagine the body moving inside that structure, and use lines to show how the body disorts that basic shape.
Imagine the guy standing in the most formal way, and what parts of the suit would be tight, what would be making folds.
Once you have the hang of that, imagine what would happen when he goes into his current pose.
You can use some of the lines you already have in your figure, for example the line you used to imply the scrotum could very well be a fold in the pants.
Suit shoulders usually have shoulderpads inside, so the shoulders should be stiff as if he was still with his arms hanging down, only right beneath the shoulders should be wrinkles showing the vast difference between the suit's-shoulders, and the current arm position.
Suits usually have a stiff chest as well, that tends to give the sense that guys have more chest muscle than they do, but in this pose it would actually sag down. the way he's bending would also create a crease at his stomach. it would be nice to show the lower part of his...jacket hanging a little above where it should, since the shoulders dragged the whole jacket up
and for the love of god have fun with that TIE! it's the most suggestively phallic piece of clothing I can think of and you have a guy in a suit dancing tribally...SOMETHING MUST BE DONE!!
with the elbows and the knees, think how the suit is creaceless when they are vertical, but once you bend it, the part bending inwards gets collapsed on itself and creates creaces.
Also, when there's something sticking out, it makes the clothe around it hang down, and this creates a bunch of lines of tension pointing towards whatever sticks out. You could do this with the knee to our right, but in the particular edit I made it seemed like a bit too much.
http://emugif.fcmgame.com/Study recent "King of Fighters" sprites, they are really good at simplifying what goes on with folds.
http://www.youtube.com/watch?v=YPAGU3o5idMMaybe the kid's story and matrix agent clips in general would be good refference too...because of all the suits doing unruly movements.
