11) Body PowderIn certain countries, you'll see locals using powder all the time to help keep dry. I have to admit that even a small thing of body powder (like Gold Bond) doesn't always make the cut when I'm trying to trim down the weight of my bag.
10) Cooling TowelThis is a must-have for a friend of mine who absolutely melts in the heat. A water-activated Kool Tie or Cooling Towel will help keep you cool for hours.
9) Sweat ClothKeep a washcloth-sized travel towel in your bag and use it to mop up sweat off your face and neck. It's great on hikes, in a hot bus, or anywhere really. I'm not sure if it keeps you any cooler, but it sure feels better to be a bit drier.
8) No MakeupI'm not the travel-with-makeup type of gal anyway but having that stuff on your face just makes you sweat even more. Stay natural.
7) Shave Your HairIt definitely helps to tie your hair in a ponytail or keep it back in a headband, but even better ... shave the underneath! About 2-3 inches gets the hair off your neck and is so much cooler!
My friend who melts in the heat? She loves using a buff (yeah, like on Survivor) to keep her hair pulled back and she says the fabric is cooling.
6) SkirtsSkirts and dresses are generally cooler than pants because you have air flow. I personally find maxi-skirts too hot for me even if they are super performance fabric.
With skirts you need to watch for thigh chafing though, which can get very painful. I travel with a pair of Jockey Skimmies slip shorts to use as my underwear with a skirt if I'm having chafing issues which unfortunately happens a lot in the heat, especially now that I'm heavier.
Guys, you can wear a sarong in many countries and not be out of place at all!
5) Travel UndiesYes there is such thing as performance / travel underwear; for both men and women. I really feel this makes a big difference in dryness and comfort. ExOfficio Give-n-Go is so far the best brand I have tried. They dry in no time at all, don't have a cotton crotch, and are thin and comfy.
Ladies, I tend to find thongs to be more uncomfortable in tropical climates so you might consider wearing bikinis or even going commando when traveling!
4) Cold ShowersCold showers. Lots of them. 'Nuf said.
3) SandalsYou know that moment when you're in a hot climate, you take off you're shoes and socks, and ahhhh so much cooler!? Yeah, closed shoes do not help keep you cool. Sandals all the way, without socks of course. ;)
Hiking sandals or even rugged flip flops can do the trick almost anywhere. I seldom have found a hike that I can't do in a pair of Tevas or Keens.
2) Performance ClothingThis is definitely the most important thing on the list (other than ice cream, ice cream trumps all). All of your clothing should be wicking (drawing moisture away from your body), breathable (drawing air/heat away from your body), quick-dry (keeping you drier from sweat), and lightweight (not bogging you down). Travel or active-wear fabrics are a must-have if you are trying to beat the heat.
You'll also want to avoid clothing that shows sweat. Your best bets are black, white, or patterns.
P.S. This goes for hats, too. If you throw on a regular baseball cap, you're going to increase your body temp (and your head temp) by a ton. Go for a moisture wicking cap like the ones from Arctic Cool or Sunday Afternoons.