Don't over bake and dry your brownies out.  Brownies are done when the edges begin to pull away from the sides of the pan and the center is set, not wiggly. When you insert a toothpick there should still be a smear of brown color on the toothpick, but not wet batter.  These brownies are fudgy so if the toothpick comes out totally clean they are probably over baked.