1. Prepare yourself: Read the recipe from start to finish — twice — before beginning.
2. Shop with this list: Our cookie recipes call for large eggs, all-purpose flour and unsalted butter, unless otherwise noted. For optimum results, invest in fresh baking powder, baking soda and spices. (Our tip: Buy spices in the bulk section; you'll save money by purchasing only what you need, and the flavors are generally more potent.) Because butter is a key cookie building block, buy the best your budget allows. Many local pastry chefs rely upon Hope Butter. It's widely available and made at Hope Creamery in Hope, Minn.
3. Equip your kitchen: Use flat, shiny and rimless medium- to heavy-gauge aluminum baking sheets. Skip the nonstick and use (and re-use) parchment paper or silicon (such as Silpat) baking mats.
4. Measure carefully: Spoon flour and powdered sugar into the measuring cup (rather than using the measuring cup as a scoop) and level ingredients with a straightedge, such as a knife. Butter is at room temperature when a light touch leaves a slight indentation, about 30 to 45 minutes.
5. Reach for the spatula: When mixing dough, take a moment to scrape the bottom and sides of the bowl, and then resume mixing.
6. Stay in shape: To keep round refrigerator cookies from going flat, place the plastic- or wax paper-wrapped logs on a level shelf in the refrigerator and give the dough a quarter-turn every 15 minutes for the first hour.
7. Bake evenly: Preheat the oven for at least 20 minutes. Adjust baking rack to the oven's middle position. For true accuracy, invest in an oven thermometer (Target sells a reliable model for about $7, an expenditure that will more than pay for itself). Use one baking sheet at a time in the oven, rotating it halfway through baking time. Cool baking sheets completely between batches — hot baking sheets can cause dough to spread — by alternating among several baking sheets, or running hot ones under cold water.
8. Store wisely: Most cookies remain fresh for up to a week when stored in an airtight container at room temperature. Store different cookies in separate containers. Freeze cookies undecorated. When ready to serve, thaw and decorate.