Some good oils for French fries include peanut oil, per the recipe from Emeril Lagasse, and vegetable oil, per the recipe from Martha Stewart. Most oils that contain high amounts of saturated fats work well for cooking French fries.
One of the most important things to remember when frying French fries is to use oil that has already been heated before. When cooking the French fries, the water content in the potatoes repels the oil and creates a non-satisfactory product. After the oil breaks down a little because of heat, the potatoes begin to absorb it better.
The recipe from Lagasse suggests that cooks fry the potatoes once, and then let them set in the refrigerator for up to 2 hours. After the potatoes get a chance to rest, cooks can fry them again with an oil temperature of 350 degrees Fahrenheit before serving.