Run each side of your good knife over a honing steel 3-4 times at the angle it was sharpened at before putting it away to realign its edge.
Get your good kitchen knives professionally sharpened once a year.
Never allow the edge of your good kitchen knives to come in contact with anything other than food and cutting board. Anything else will nick the blade or dull it.
Never "chop" with your chef's knife. The motion is a circular slice that pushes the knife through the food and back again.
The chef's knife is the workhorse of the kitchen. The right knife is different for every person. Test how several feel in your hand before you make a purchase.