How should I properly season cast iron pans to ensure their longevity and optimal cooking performance?

To properly season cast iron pans for longevity and optimal cooking performance, first wash the pan with hot water and dry it completely. Then, apply a thin layer of vegetable oil or shortening to the pan, inside and out. Place the pan upside down in an oven at 350F for an hour. Let it cool in the oven before using. Repeat this process a few times to build up a good seasoning layer. Avoid using soap or harsh scrubbing, and always dry the pan thoroughly after each use.