Howdy,
I posted this previously, and not knowing how to link to it, I've copied it verbatim. Hopefully I'm not ignorantly breaking any posting rules. Avoiding blisters has become some kind of wierd passion for me.
If you want a more thorough blister lecture, you can read about it on the thorlo website.
Here's my old posting....
Using spray anti-perspirant should work, since the cause of blisters is friction and wetness. I can't think of what it is doing to the feet, since our feet are designed to sweat, but for short term cases its probably ok.
The best advice I've ever gotten is to get properly fitted walking shoes and to wear non-cotton socks.
The first bit of advice is to go to buy walking shoes at the end of the day, wearing the socks you'll be wearing in the shoes. If you've not been measured in a while, get a foot measurement which a braddock device. Its the thing with the slides, then try on a few pairs in the sizes around your foot measurement. Good walking shoes shouldn't be tight or require much of a break-in period. The toes shouldn't be jammed into the front of the shoe, and the widest part of the foot shouldn't be pinched. Don't expect the shoes to stretch much.
Almost any good brand of sneaker should work, though you'll find it tougher to find shoes which come in the wider widths (which is what most americans probably need more than narrower). The only major sneaker maker who I've found makes wide (eee or more) shoes is New Balance.
The second bit is to not buy socks with _any_ cotton in them. All it does is absorb sweat, compact, and stay wet all day. There are many different brands of non-cotton, 'wicking' socks on the market now. Most have acrylic yarns such as the cool-max brand, but they all work to absorbs sweat from the foot and wick it away. Some seems to wind up in the sneaker, but if you have 'crew' socks which come above the shoe, some will wick up and out and will evaporate naturally (which means you'll dissapate heat, unlike using anti-perspirant). Some 'wicking' socks are made with wool, which also wicks moisture to an extent, and if you're in a cold climate (not the case with WDW, but....) will keep you feet warmer since they dry from the inside.
The socks I prefer are made by a company named 'Thorlo', though Wigwam and other make similar quality socks. The thorlos' are more expensive ($8-12 per pair), but include extra cushioning at the pressure points (heels for example), and a nice open weave in the less impacted areas. They're supposedly designed to help with 'shear', which is the friction aspect of getting blisters.
Adding to this advice, some tips:
1) Bring two pairs of comfortable, well fitted walkign shoes. Alternate them daily, esp. if they get wet.
2) Change socks mid-day, giving both your feet and your shoes time to air a little.
3) Keep your shoes clean. Dirt getting into the pores of the leather or man-made upper will actually inhibit the ability of the shoe to dissapate vapor and heat. All you need to do is wipe them off with a damp cloth at then end of the day, or if you're anal like me, wash them with saddle soap. If you have suede, use a suede brush instead.
Finally, if you do manage to get a blister, make sure it gets cleaned properly, put a bandage on it, and use moleskin _around_ the blistered area to provide a buffer to keep the tender area from getting rubbed too much.
Hope this helps,
Joe