Do you like blisters? Don't read this guide!
Before the hike we always tape our feet as protection against blisters. This is done by using about 20 cm of sport tape. This tape can be bought at most sport shops or at the drug stores.
Place the tape about 12 cm above the heel. Angle the foot upwards and pull the tape down over the heel and under the foot. Observe that it's important to angle your foot otherwise the tape will tighten when you walk up hills. Also check that the tape is flat with no folds.
This method is developed under many long and painful experiments under several years ;-)