How do i sharpen a kitchen knife?

The sharpeners you can buy at a store will do an OK job. My advise is to find a place near your home to have them done professionally. Most professional chefs will know hoe to sharpen a knife but will even then still send them out to have them done. It usually is pretty cheap, a couple dollars per knife and it will be a lot sharper than a gadget from the store will get it. Also invest in a honing steel. Those are the long things you see chefs rub their knifes on. They do not actually sharpen the blade but they realign it, and it helps the blade to stay sharper longer.