Gently hold the lemon in one hand and the zester or grater in the other hand.
Rub the lemon up and down the rough side of the zester until the peel begins to come off
Keep rotating the lemon around so that only the peel is removed. You don't want any of the white pith just below the peel. The pith is bitter tasting. Only grate the peel.
Notes
Always zest a lemon, lime, or orange first before juicing.
Wash and dry your citrus before zesting. Rinse the lemon thoroughly under cool water to remove any dirt or wax on the surface. Pat it dry with a clean towel before zesting.
Choose a fresh and firm lemon. Fresh lemons will have a stronger flavor and will be easier to zest.
Rotate the lemon while zesting. You don't want to grate the lemon for too long in any one spot. Keep that lemon moving.
This method works with all citrus.
Methods using other tools are included in the post above the recipe card.