1. Keep them sharp! They are safer and much more fun to use that way.
2. Keep them clean.
3. Don't wash them in the dishwasher. It will make them dull from banging around.
4. Do not use glass or ceramic cutting boards. They will dull your knives.
5. Do not keep them in wet sheaths. Do not store them in sheaths.
6. Use steels and honing rods only to maintain the edge. They will not sharpen your knives.
7. Use a ceramic steel, and gently drag knife downwards at a 20-25 degree angle to straighten out the edge.
8. Do not use them to pry things open.
9. Don't stack them on top of each other or keep them in a drawer where the edge can hit other things.
10.Use the right knife for the right job. Blunter, heavier edges should be used to cut harder food (squash, potatoes).