I learned this in my woodcarving club and it is valuable for our kitchen knives as well.
You can use the "back" of a real leather belt to sharpen knives!
Don't use your finger to test the sharpness!!!!
If you must test, woodcarvers will LIGHTLY touch their finger nail on the blade. You can tell if it's sharp by the feel of the knife on your nail.
Note: Don't try to rub the knife back and forth like an olden day barber in the movies! That can cause the knife edge to create a ROLL of metal on the edge of the knife blade, dulling it.
I know this may not seem important to many people, but I like a sharp cooking knife. This probably comes from living in Japan. Almost every household has a whetstone. We tend to sharpen the knife at least once a week if not every time we use it.
We keep all of our knives for cutting, peeling, filleting, and other uses in a butcher block style holder. They stay very sharp all the time.
For a quick touch up on your knives, vigorously rub the blade on a green scratch pad, such as the Scotch brand. An old one will do. You will be surprised at the edge it will put on your knives.
I have found that to keep a knife or scissors sharp, cutting kitchen foil is a simple answer.
Keeping your knives sharpened will cut your cooking preparation time considerably. By Robin
Don't have a sharpening stone? Use a ceramic mug with a rough base. Turn mug upside down and using your opposite hand, hold the mug in place with the mug handle.