In this course, you're making more than cookies - you're also learning good basic baking principles. Here are some highlights: Always cream your butter at room temperature. Do not over-whip the butter - you'll lose the air you've worked so hard to incorporate. Always combine wet ingredients with wet ingredients first. Then fold that mixture into your combined dry ingredients. Once more, everything should be at room temperature. Crack eggs into a separate container before adding to the overall mixture. That way if an egg is bad you haven't ruined all of your ingredients. Remember to only mix until ingredients are combined. Over-mixing makes tough cookies. Finally, remember to give your cookies space on the baking tray. They'll spread out as they cook.