From Consumer Reports & their blog, Consumerist. A quick summary: If you have better-quality steel knives, don’t waste your time... Sharpen them yourself at home or take them to a professional sharpener.

This is a link to the blog, which has a link to the paid content on Consumer Reports Website

Most home cooks need to sharpen their knives only once or twice a year, but the importance of a sharp knife cannot be overstated - it will make you a better, safer cook.

Never sharpen your knives on an electric grinder or file.  Many shops may do it this way, but it kills the blade and greatly shortens its life span.  Using a grinder is fine for your scissors and lawn mower blade, but not for your favorite Santoku.

Hone your knives at least once a week on a sharpening steel.  It's a part of almost every knife set, and you've probably seen your butcher use one right before making that special cut you requested.  Just remember, a steel won't sharpen your knife.  It simply maintains the blade's edge, which does make for a better cut.

A steel is used for conditioning or re aligning the knife edge in between professional sharpening. It should be used often.

• Hold the sharpening steel vertically firmly in your hand at arms length in front of you.
• Hold the knife by the handle. The tip of the blade should point upward.
• Hold the knife at the proper angle with a slight pressure over the steel.
  • 15 degrees for Japanese style knives
  • 20 degrees for German style knives
• Move the blade from the bolster (or back wide part of knife) to the point.
• Move the wrist but not the arm.
• The conditioning is done after about 10 strokes of the knife over the steel on each side.

Always hand wash with soap and hot water after every use. The acidity of some foods can damage the edge, discolor the blade and pit the metal. Tomatoes and citrus are particularly harmful. Hand dry and return them to storage rather than letting them sit around.

Never put your knives in the dishwasher. The heat of the dishwasher may ruin the temper of the steel to the point that it will not hold an edge. Plates and other items in the dishwasher can hit your knives dulling the edge. Salts and acids combined with high, humid temperatures may damage tempered or Damascus steel blades.

Always store your knives in a block or wall magnet if available. If you must put them in a drawer with other knives and cutlery, keep them in card board or plastic sheath. Inexpensive sheaths can be purchased from you local kitchen stores.

Hold it in your hand. There are many different styles of knife handles. Not all of these will feel good in your hand.  Some are round, some square, some have the tang extrude from the handle.  The knife you buy should be a pleasure for you to hold.

Price matters. A good knife can be costly, but consider it a lifetime investment. If it is taken care of, it can become an "heirloom." That means washing and drying it by hand, plus sharpening when needed.

Know the knife's limits. Ceramic knives, for instance, can break if dropped. And using knives on a glass cutting board will dull them.

Never use a glass, ceramic, marble, or granite cutting surface. These will dull and damage the cutting edge. Knives need a board surface softer than the knife itself. The best cutting boards are wood or plastic. The blade will cut into the board, but that is what the board is for. The most common cause of wear of the cutting edge of a knife is due to contact with the cutting surface.
 
Use plastic cutting boards for meat preparation.  These can be safely sanitized in the dishwasher after every use. 

Wood Cutting Board Care

General
Scrub it down with hot water and soap after every use
Wiping down a wood board with food grade mineral oil every so often will seal the wood from things embedding into the surface and causing food contamination
Never put your wood cutting board in the dishwasher and keep out of direct sunlight

Monthly
Bathe in warm sudsy water and sanitize in one 1 gallon of water with 1 tablespoon of bleach

Semi-Annually
Rub down with kosher salt and water.  This smoothes out scratches and kills bacteria

Annually
Clean and sand down with 120 grit sandpaper, then rub down with food grade mineral oil

Use the right knife for the right job. Every knife has a specific use and you should use the proper knife for every cutting task. To get the best use out of your knives you need to keep them very sharp. A sharp knife is much safer than a dull knife. Selecting good quality knives is very important, a knife should fit your hand, be quite comfortable and should only be used for it's intended task.

Chef Knife
This is the cooks most important and versatile cutting tool. This all purpose knife is used for a variety of cutting and chopping work, as well as slicing and mincing. The blade is normally 8 to 12 inches long and a few inches wide.

Utility Knife
This smaller, lighter knife is used for light cutting and slicing jobs, often on fruits and vegetables.
The blade is usually 5 or 6 inches long

Bread Knife
This is used for slicing breads, cakes and pastries.
The blade is usually 8 to 10 inches long and serrated.

Boning Knife
Used for separating raw meat from the bone. It has a thin short blade and is often stiff or flexible.
The blade is usually 5 or 6 inches long.

Filleting Knife
Used for separating raw meat from the bone. It has a thin short blade and is often stiff or flexible.
The blade is usually 5 or 6 inches long.

Carving Knife (Slicer)
Used for carving large roasts, turkey and also filleting very large fish. It has a long slightly flexible blade.
The blade is usually 10 to 14 inches long.

Cleaver Used for chopping meats and cutting through bones. It has a heavy rectangular blade.
The blade is usually 10 to 14 inches long.

Paring Knife
Used for peeling, slicing, trimming and dicing small fruits, vegetables and cheese.
The blade is usually 2 to 3 inches long

Tourne Knife (peeling)
Used for peeling, slicing, trimming and dicing small fruits, vegetables and cheese.
The blade is usually 2 to 3 inches long.

Steak Knife
Used for cutting steak, chicken and other main courses.
The blade is 4 to 5 inches long and can be wide or thin, serrated or smooth.