The powerful adhesive of duct tape holds it true to the outline of your skin and the tough, plastic outer tape skin reinforced with fabric can withstand almost unlimited friction. The friction points on your skin will then have an additional layer of skin - the duct tape. Gary's method follows, with a few of my time-tested additions. Remember a few general duct tape rules. Choose a good quality duct tape with a visible fabric core, not a plastic cheap imitation.
Many hardware stores carry several types of duct tape.
Although the tape is sometimes available in a variety of colors the common silver tape works the best. The tape is applied over the danger spots where blisters frequently occur. Don't apply tape where it is not needed. Use only a single thickness since additional layers become too hard and unyielding. When the tape is applied, that part of the foot should be flexed to its maximum extension.