I was looking at the Massive Black website, and in the portfolio is an image of some bikers outside a biker bar.
Who did this one, and in what medium? And how did they do the denim texture? The jeans absolutely blew me away.
didn't see the exact image, but the process is probably the same.
Do study's of pants and wrinkles.
Use lots of reference.Google pant images and refer to those as you paint your own pants.
Use overlays or other layer effects in Photoshop to add some texture and details.
Design your wrinkle forms. Check out J.C Leyendecker.