The goal is to pack with one bag. As much as possible, pre-plan your itinerary, figure out the specific items you'll need for your trip and stick to that list — if you start contemplating what to bring the night before you take off, you're doomed. But packing light doesn't have to mean going without. Just be strategic about what you bring. Mix and match everything, so you can coordinate more outfits with fewer clothes. If you pack all neutral pants or skirts, for example, you can use your patterned tops with any and all bottoms. Remember also that layering for colder weather is always better than bringing big, bulky pieces; on hot-weather trips, include a light sweater or jacket. Shoes are the big space hog, so limit yourself to two pairs (and don't forget that you can pack socks or other small goods inside your shoes). Ditch your toiletry bag, since you'll have to put all your stuff in a Ziploc bag to get through security anyway. And finally, remember the frequent-flyer's best friend: wrinkle-free everything.