The most important thing you can do is rotate your pans and cookie sheets. If the baking time is scaled at 22 minutes, after 11 minutes, reach in there (oven mitt on, of course!) and rotate the cookie sheet to switch the front to back. If you have decided to cook more than one sheet at a time (sometimes successful), be sure to rotate top-to-bottom, and also front-to-back. This simple effort will keep all your baked goods evenly browned.