Pack only half the clothes that you will need. If you are staying for a week, pack four outfits. Stick to one color scheme so that each top will coordinate with each bottom and your shoes. If you are a shopper, bring one less outfit than you need and plan to purchase the extra outfit in your destination country. Halfway through your trip, go to a local laundromat and do your laundry. This is a fun adventure! Sit at a nearby pub while your laundry is washing and enjoy the local brew.
Bring one pair of shoes; two at the absolute most. Men can get away with wearing a nice pair of dark leather walking shoes that double as dress shoes when going somewhere nice. Women have it a little harder; wearing tennis shoes while traveling and packing the thinnest pair of dress sandals you own in your suitcase is usually the best option.
Stay at a hotel that offers toiletries. With the new carry-on baggage restrictions, you probably will not be able to pack enough shampoo and conditioner to last for your whole trip. If your hotel does not provide toiletries, purchase them at a local drugstore. It is actually quite fun to see the different cosmetics and health items available in foreign countries.
Bring a translation guide that tells you how to say helpful phrases in the local language. Finding necessary items at the local store is a lot easier if you know how to ask for them.
Avoid buying a ton of souvenirs. Let your experiences be your souvenirs. Remember, whatever you buy must fit into the suitcase when you fly back home!