Heat the oil to 400 - 460 degrees. (If the oil smokes, its too hot.) Test the oil with a couple of kernels. When they pop, add the rest of the popcorn, cover the pan and shake to evenly spread the oil. When the popping begins to slow, remove the pan from the stovetop. The heated oil will still pop the remaining kernels. Do not salt popcorn until all the kernels are popped; salting beforehand toughens popcorn.