Cut correctly. An up-and-down motion when cutting food dulls the edge more quickly than if you cut using a rocking or sliding motion, keeping the blade always in contact with the cutting board. The board should be wood or plastic rather than anything harder.
Hone routinely. Use a honing steel every time you’re about to put the knife to work. Hold the steel vertically and brace its tip against a tabletop as you run each side of the blade edge against the steel, from heel to tip. A true sharpening can be done annually, using a foolproof handheld tool like an Accusharp. “Skip electric sharpeners, which strip away too much metal.”
Wash and store. Always hand wash a knife. Store it in a plastic sheath, on a magnetic strip, or in a knife block that keeps the blade from resting on its cutting edge.
Source: Real Simple