Soaking the potatoes after they're cut draws out some of the starch which is naturally present in potatoes. This will result in a crispier fry. A thirty minute soak in cold water does the trick but you may soak them longer if you want. After soaking, be sure to dry the potatoes before you fry them. Drain off the water and dry the potatoes on a clean lint-free dish towel or paper towels.