This is everything Jake and i did on our Indy.
While the outfit is on the body...Water treat everything put wrinkles in the jacket and fold the shirt out so it will be more. Put wrinkles in jacket while wet too by folding it up the arms.
Cut the lining out of the jacket turn the sleeves inside out spray them with fabric stiffener. This is how you get the wrinkles to stay in.
Spray the jacket with some matte sealer to take away the shine.
Glue the jacket lapels down the the jacket so they lay flatter.
Weathered the jacket with different shades of brown, black, and lighter brown acrylics and re-seal it. Also used some chalk pastels for a dust effect.
Dry brushed a lighter brown over the wrinkles with the sleeves pushed up so they look more worn.
Tuck the extra jacket material behind the figure and put his arms down to his sides to keep the extra material from sticking out. It will keep the jacket looking more slim this way.
Hope this helps