You may not notice how much your knives have dulled until you are faced with slicing and dicing endless tomatoes, potatoes, and other ingredients for a few hours straight.
To use a sharpening steel, hold the steel in your left hand and the knife in your right hand, with the cutting edge toward you. Lay the blade on top of the steel and raise the back of the knife 20 degrees (you'll want to keep the knife at this angle at all times). Place the heel of the blade at the tip of the steel and using light pressure draw the edge across the steel in a sweeping, curved motion (as if you were shaving off a thin slice of the steel) until the tip of the blade points toward the handle and guard of the steel. Then place the blade under the steel and repeat. Always give each side an equal number of strokes. You can also use a similar procedure with a sharpening stone. Serrated and fine knives should be professionally sharpened.