A corn is a thickened area of skin that on toes or fingers. They are meant to protect the body against damage from pressure. For example, if you regularly wear shoes that are too tight or constricting, you might develop a corn on your outer toes, caused by the rubbing and pressure of the shoes. Once a corn is formed, it's there to stay unless treated aggressively.
Wear shoes that fit well. According to ePodiatry, tight footwear is one of the main causes of corns. When trying on shoes, make sure your toes are not too constricted and you're able to at least have some room to wiggle them. Make sure also that your skin doesn't rub too hard against the side of the shoes.
Use a pad to ease pressure. If your feet are wide, you might end up experiencing pressure or contact rubbing no matter what type of shoes you wear. In that case, a small adhesive pad can help. These are sold at pharmacies under names like corn pads. They're used to prevent pain from existing corns but can also be used to prevent them.
Soak your feet at the end of the day. Place them in warm water and wait for a few minutes until your skin softens. Then file any rough skin patches you can find. This will prevent corns from forming in areas that are already suffering from the pressure and rubbing. Medical News Today suggests also using a pumice stone to soften the skin.