I can't believe that I forgot Miami Vice. Check out Breakfast Club, St. Elmo's Fire, and any John Hughes 80's teen flick for ideas.
You can consult "The Official Preppy Handbook" for some Muffy and Biff ideas.
Also big moussed hair with butterfly clips, pink zinc lipstick, blue eyeshadow, slouch socks, and acid wash jeans was a big look in the late 1980's. Ah nostalgia! I just described my freshman floormates.