Listed below are the steps for seasoning or re-seasoning a skillet:

1.  Wash with hot, soapy water.
2. Rinse and dry thoroughly.
3. If there’s any rust on the, pan, sand it lightly with fine grained sandpaper.  Apply Coca-Cola to the rust spots and leave on for 10 to 15 minutes.  Wash again with soapy water, rinse,dry and put the skillet on a burner over low heat to dry any excess moisture.
4. If there is no rust, after drying the cookware all over, apply a light layer of cooking oil (vegetable oil, NOT olive oil, butter, or margarine!)  all over the pan with a paper towel, rubbing even the handle.  The pan should have a light sheen to it.
5. Place the skillet upside down on the middle rack of the oven and preheat the oven to 400 degrees (with the pan inside).  Put a piece of foil or a baking dish on the lower rack to catch any drips of oil.  Let the pan cook in the oven for about 2 hours.
6. Turn the oven off and let the pan cool (upside down) in the oven.
7. Take it out, wipe it down with with a clean paper towel, and it is good to go.
8. If your pan has taken on a slightly brown color, you can repeat the process which will further season the pan and darken its color, improving its appearance.  This will also happen over time.

The best thing to do with your cast-iron skillet is USE  IT!    The more you use it the better it gets.