As a global traveler and outdoor photographer, I've learned that "going light" has advantages beyond avoiding having to check your bags. The less stuff you have with you, the more time and energy you can devote to living the experience rather than trying to transport and keep track of your gear.
Pack for your mode of transit
Traveling by foot isn't the only mode of travel in need of lightweight thinking. Flying in small four-seat planes in remote places like the Okavango Delta in Botswana, baggage needs to be soft and small, as the planes have minimal storage space. You don't want to be worrying about hauling a bunch of heavy bags when you're standing on a dirt air strip in the bush and your pilot tells you to back away from the plane as a bull elephant wanders onto the air strip. Additionally, environmentally threatened places frequently limit access to transportation with the least impact, like the Galapagos Islands where visitors are restricted to small vessels.
Choose versatile, quick dry clothing
Traveling light means choosing clothing with care and picking items that are versatile, compact, and lightweight. I cannot say enough about quick-drying shorts and shirts - a few pairs of each are all I need for many trips. And I rarely travel without my zip-off pants which effectively double your wardrobe, allowing the freedom to hike in shorts, and converting easily in deference to local customs in town. The quick-dry technology in all this clothing allows you to easily wash and dry mid-trip.
Obviously, if you are carrying a heavy pack, you must wear proper hiking boots for support and safety. But for many trips, I have found that sport sandals are perfect all-around footwear. Sandals - such as Tevas or Keens - are lighter and more comfortable in many climates; for cooler weather, add socks.
Stash an extra hat
For sun protection or warmth, don't forget the essential hat. In fact, I always pack an extra as I have lost quite a few overboard (sail boats, speed boats, airplanes, and general wind gusts).
Bring an LED headlamp
A flashlight is nice until you experience an LED headlamp - less bulk and less weight combined with significantly higher utility. Beyond reading in bed, I really put my headlamp to the test in the Amazon basin. On a night hike through the rainforest, we saw a beautiful Emerald Boa Constrictor hanging on a branch over the trail. Unfortunately my camera flash batteries died and I missed the picture (see camera battery tip). The next day we took the same trail and saw the snake coiled in the same location (they are nocturnal). I decided to go back after dark for a photo, but the guide wasn't available, so I ventured back on the trail by the light of my headlamp and got the picture.
Don't forget camera batteries
For those of you who would rather not venture down a dark path at night without a guide in search of a rather large snake, remember to pack extra camera and flash batteries and keep them available at all times.
Always bring a towel
To quote The Hitch Hiker's Guide to the Galaxy, "A towel is about the most massively useful thing an interstellar hitchhiker can have." And even on planet Earth, a small ultra-absorbent pack towel finds its way into my bag on every trip. It has been handy both for spontaneous swims and drying other gear.
Believe in stuff sacks
Several small, ultralight, silicone nylon stuff sacks are highly versatile for the lightweight traveler. They are practically weightless, great for arranging gear, stowing dry or wet clothing, and carrying home souvenirs. I also fill these sacks with locally bought grain or rice, which makes a great bean bag to use as a travel pillow or for stabilizing your camera (particularly when shooting from a vehicle).
Be prepared with a multi-tool and duct tape
While you do not want to be weighted down carrying a toolbox across the Great Sahara, a few simple items can save a trip from disaster. A small multi-tool, such as a Leatherman, can fix a multitude of problems from luggage repair to opening that can. And if there is a problem that can't be at least temporarily solved by duct tape, I have not discovered it
Ship ahead / mail back
With all the new airline regulations, many travelers are shipping gear to avoid airline baggage and lighten their load. I have been doing this for years, especially on longer journeys involving multiple climates or specialty gear. If you are scuba diving on the first part of your trip, ship that gear back home before you trek inland with a bag full of flippers and wetsuits. Alternatively, if you're trekking first with a week of diving at the end of the trip, ship all that dive gear directly to the resort or dive site.