How can I effectively rototill hard dirt?

To effectively rototill hard dirt, first, moisten the soil to make it easier to work with. Then, adjust the depth of the rototiller blades to penetrate the hard dirt. Start by tilling in one direction, then go over the area again in a perpendicular direction. Repeat this process until the soil is loosened and aerated. Avoid over-tilling to prevent damaging the soil structure.