Making fresh-cut french fries at home isn't difficult, but it does require a bit of advance preparation. You'll need a countertop deep fryer or a deep pot to hold the fat safely, and a candy or deep-fry thermometer to monitor the temperature. It's also helpful to cut the fries in advance, because that's a time-consuming part of the project. Cut potatoes brown quickly if they're exposed to the air, so you need to immerse them quickly to keep them from turning brown.
Potatoes brown when an enzyme inside their cells reacts with oxygen from the outside air. To keep your fries from browning, squirt 1 or 2 tablespoons of lemon juice into a large bowl and fill it with cold water. The acidity of the lemon juice inhibits the browning enzyme's ability to react with oxygen, and so does the cold of the water. Just as important, the water limits how much oxygen can reach your cut potatoes. Refrigerate the bowl to keep your potatoes cold, if you won't be cooking them right away. When you're ready to cook them, drain them well and then dry the potatoes on clean paper towels to limit any spattering from water hitting the hot fat.