One of the keys to a fluffy, moist cake is to use room-temperature ingredients. I recommend letting the ingredients sit out on the kitchen counter for 30-45 minutes before you plan to start baking. Another secret is to take care not to overmix the batter. An overmixed cake may be dense and chewy instead of light and tender. If you’re worried about overmixing, I recommend folding all the ingredients together by hand.