Use flat baking sheets or shallow pans to bake cookies – using regular baking pans will prevent cookie dough from baking properly. Once a cookie sheet warps or curls, get rid of it. If you’re serious about cookies, find a restaurant supply house that sells to the public and buy standard baking sheets called “half pans.” They’re indestructible, heavy enough to break your toes if you drop them, and too big to fit into the dishwasher. However, they make great cookie pans.

Become a regular user of parchment paper; use it to line your cookie sheets, no matter what the recipe says about greasing, buttering, or flouring your pans. Cookies slide right off parchment paper unless they have really sticky ingredients like caramel or toffee. If your recipe does include such sticky stuff, lightly butter the paper first. Also, cookies baked on parchment paper seldom scorch unless you really, really leave them in the oven too long. Finally, it’s easier to bake large batches of cookies when you only have one or two pans, because you can put cookie dough on sheets of paper until you have a pan available. If you use parchment paper, you will never again spend one minute trying to wash charred cookie scraps and grease off your pans. Do not substitute other types of paper, such as brown paper bags. Papermaking processes can include some very toxic ingredients, but parchment paper is always food-safe.

Do not underestimate the importance of preheating the oven when you are baking cookies. If you start with a cold oven, the first pan will take forever to cook, and then you’ll be adjusting the time for each pan that follows – a sure recipe for at least one pan of burned cookies.

Most cookies need to bake for 8 to 12 minutes. Check the first pan after 8 minutes, and adjust your time or oven temperature if you need to.

Always use wire racks to cool cookies, whatever the original recipe says. Don’t cool them on wax paper, newspaper, parchment paper, the countertop, or anything else. Wire racks allow the cookies to cool on both sides, and cooling the bottom of the cookies keeps them from getting sticky or soggy. Besides, who wants melted wax on the bottom of their cookies?

If cookies become dried out from overexposure to air, you may be able to rescue them by putting them in an airtight container with a couple of slices of soft bread or a couple of slices of apple. Apple slices work better, but will impart a slight apple flavor to the cookie.

Don’t skimp on your ingredients. Use real butter – not margarine or spreads. Using butter improves the taste, but also is critical to texture; cookies made with butter won’t wilt on a hot pan waiting for their turn in the oven, and will hold their shape better than those made with substitutes.

Old recipes almost always called for sifting flour, or sifting dry ingredients together. There’s a good reason for that – before post-Progressive Era commercial food handling practices became common, one often found odd crop-harvesting debris in flour or sugar, or clumps from poor moisture control, or uninvited crawling creatures. In other words, there used to be compelling reasons to sift dry ingredients through a filter before eating them. Moreover, some Old Testament-based religious practices required diligent removal of insects from food. These things aren’t much of a problem for most of us any more, so sifting generally isn’t necessary.

That said, sifting does increase the volume of a given weight of flour ever so slightly, so if you’re fussy about the issue, go ahead and sift. For the rest of us, the slight change in the volume of a cup of flour which is created by forcing a few more air molecules in between the flour molecules isn’t enough to make any difference in taste or texture.*

*The texture of flour doughs and batters is affected not only by the volume of flour but the type of flour used (low- or high-protein), fats and sugars in the dough, the dough’s acidity, and the dispersal of starch in the dough. Lightness doesn’t depend on how much flour is used, but on the development of gas bubbles in the dough caused by leavening agents, which weaken the gluten in the flour. See the excellent and frankly indispensable On Food and Cooking: The Science and Lore of the Kitchen, Harold McGee, Scribner 2004.

No oven is exactly calibrated, no oven heats evenly, and it’s way too expensive to keep calling the repair people over for a visit. Go to the hardware store and buy a flimsy-looking oven thermometer on a hanger for about $5. Hang it on an oven rack, and turn the oven up to 300 degrees. Let the oven heat up, and check the thermometer to see how far off the setting is. If your oven is set for 300 degrees but the thermometer reads 320, then you know you need to dial back your oven setting 20 degrees before you bake. Finally, there will always be hot spots and cold spots in your oven. If your oven is electric, this will be more bothersome than if you have a gas oven. To solve this, you don’t have to go out and buy a convection oven. Just cook one pan of cookies at a time, and rotate the pan halfway through the baking time.