While a lemon zester can be a handy addition to your lineup of kitchen tools, owning one is not absolutely necessary, even if you cook often. All you really need to make beautiful lemon zest is a vegetable peeler, a sharp chefs knife and a little bit of practice.
Wash your lemon thoroughly under hot water using a mild soap or veggie wash. Use a stiff vegetable brush or coarse sponge to make sure all of the dirt and wax is removed from the surface. Pat dry with a paper towel or clean dish cloth.
Use a sharp vegetable peeler as your lemon zester by carefully peeling off a strip of the lemon skin, working top to bottom. Peel only the topmost layers of the skin. If there is any white showing on the underside (the pith), you've peeled too deep. For best results, the width of the peel should be 1/4 inch to 3/8 inch wide. An average lemon yields about 2 to 3 teaspoons of zest, so peel only as much as you need for you recipe.
Place a strip of peel onto a cutting board, outer skin facing up. Smooth the peel gently with your fingertip to flatten. Using the chefs knife, cut the peel into very thin strips, about 1/16 inch wide. These thin strips are the zest. By using a rocking motion with the knife, keeping the tip down and raising and lowering the handle, you should be able to create the zest quickly.
Make finely chopped zest by chopping the strips of zest crosswise with the chefs knife, using the same rocking motion. After chopping through the zest in one direction, rotate the cutting board 90 degrees and chop again. Continue to rotate and chop until you reach the desired fineness.
Another alternative to a traditional lemon zester is cheese grater. This works best if your lemon skin is fairly dry.