There's an additional use when pressing shift when leveling. If you're standing in front of a mound of dirt you can reposition the leveling circles up and down with forward/backward mouse movement. It will start to form a slope. It seems easiest for me to start at the highest point and work your way down. Backing up your character a bit can help also. Mess with it a bit and you'll be able to make a relatively smooth dirt ramp that you can easily walk up and not consume stamina. I prefer this sometimes instead of stairs/steps.

Happy hoe times!