Use the rototiller to cut the dirt several inches deep by making passes in various directions. This breaks up the ground making it easier to move. Once you have moved that loosened dirt out of the way, repeat the process until you have worked down to the desired depth.
Just let the tiller do the work of breaking up the dirt. Then, you just move the dirt around.
Read the November 21, 2014 AsktheBuilder Weekend Warrior for an interesting story on this video.