If you are wearing shoes that you know are going to give you blisters cause the fit is a little off, a really good way to keep the blisters from forming is to use "Second Skin" bandage. This stuff comes as a liquid that you can put anywhere to act as a bandage. I find that if I put it on the spots where my shoes rub, it does a really effective job of keeping me from getting blisters. It works better then moleskin or bandages because it is adhered directly to the skin so it won't come off. The only downside is that you have to plan ahead since it takes a couple minutes for the second skin to dry, and you need to let it dry completely before you put on socks, hose, or your shoes. But it does a really great job of keeping blisters at bay.