make sure everything matches everyone else in wardrope
Make sure every piece of clothing match other pieces of clothing (Use Polos instead Dress shirts)
Personally i am trying to cut down on clothes that I bring on my trips. I probably won't bring more than 4 sets of clothes on monthlong trip (trying to avoid checking bags) and probably 2 sets of clothes on 2-3 day business trips.
Take out anything unnecessary, ie shampoo, lotion, etc.