Bake your batches of cookies one sheet at a time for 10-12 minutes, rotating the cookie sheet 180 degrees, halfway through baking. This ensures that all the cookies turn the same color instead of getting browner in the hotter parts of your oven.
Cool your cookies on the sheet for about 5 minutes, and transfer to a wire rack. Don't have a wire rack? That's ok. But think about getting one - they make all your baking look cooler.
Let cookie sheets cool before putting new cookies to be baked on them.