Measuring flour is the single most important factor in "light" baking. Baked goods made with less fat tend to dry out, so it's important to measure flour accurately. First, fluff the flour with a fork to break up any lumps. Then lightly spoon the flour into a dry measuring cup without compacting it, and level with a knife. Don't scoop the flour out of the container with the measuring cup because you add up to 3 1/2 tablespoons more flour that way. That can make for a very dry cake.
Try this Kitchen Shortcut with Blueberry-Blackberry Shortcakes.