Chill, Then Heat
After you've patiently blended peace, good will and your cookie ingredients with the electric mixer, you're probably ready to ball up that batter and throw it on the cookie sheet. But don't do it. A little trick in the subculture of cookie baking is to chill the cookie dough before you bake it. This will give your batter more body and your cookies more rise [source: Amos]. When you leave the batter in the fridge overnight, the proteins and the starch in the dough soaks up more of the liquid, which dries out the dough to result in a fuller, more delicious cookie [source: NPR].
You don't always have to chill the batter overnight, however. An hour in the fridge or 20 minutes in the freezer will suffice. If you're using margarine instead of butter in your cookies, you should always freeze the dough for at least 20 minutes before baking [source: Better Homes and Gardens]. If you're not in the mood to bake that day or even the next, you can leave your batter in the refrigerator for two to three days before baking and in the freezer for up to three months. You don't even need to thaw the frozen cookie dough before you pop it in the oven [source: Cooking Light].
While the dough is chilling, preheat the oven for at least 15 to 20 minutes [source: America's Test Kitchen]. Light-colored and very thick metal cookie sheets that don't have sides are best [source: Better Homes and Gardens]. It's a good idea to rotate the cookie sheet halfway through baking to ensure even heating.