One of the surest ways to ruin your experience is to get a blister part way through a trip. Each step aggravates the injury and attention focuses on the tiny area of your anatomy that is demanding you stop moving. Without a doubt prevention is the best answer. Anything you can do to reduce the friction on your heel or between your toes is worth considering.
Ensure that your footwear fits properly and has its laces/velcro tightened snugly
Wear liner socks – for those prone to toe blisters check out Injinji’s Coolmax toe socks
Consider applying Body Glide to problem areas on your feet ahead of time
Blisters tend to occur most when your feet are damp so carry a change of socks ($3.95 Liner Socks) or give your feet some air time