Even though you might not want to tackle a large grading job encompassing your entire yard with a tiller, it's not impossible if you're willing to do the work. That being said, you may prefer to use a tiller to grade a smaller section of your landscaping or to fix a small slope to re-route water away from your home. Whether you decide to go for it and do a large space or just fix some low areas in the yard, tilling is only part of the job; moving the dirt is the bulk of the labor.
Scoop off the layer of grass in the area you want to grade. You can use a shovel or rent a sod cutter that removes sections of grass and roots more quickly. Place the sod in a shady area and cover it with tarps.
Till the ground to break up the topsoil, digging down 4 inches. Walk the tiller back in forth across the area in parallel rows.
Scoop out the topsoil into a pile and put it to the side for later use. You don't want to waste your topsoil as filler for a low area.
Till the ground again, breaking up 6 inches of soil. To create smaller clumps of soil, first walk the tiller in parallel rows, and then go back across in rows perpendicular to the first set.
Shift the soil from higher areas to lower areas to create level ground. On the other hand, if you are trying to create mounds from relatively flat ground, move some of the soil to the designated mound area.
Shape mounds or low areas you are trying to create by moving soil around until you get the height and position you want.
Cover the entire area with the topsoil that you set aside. Spread evenly.
Walk a roller over the topsoil to pack down the entire surface, walking it back and forth in rows. For mounds, it's safer to walk the roller up and over the small hill from each side instead of trying to roll in along the side of the mound.
Place the cut or scooped sod back in place over the topsoil, and walk the roller over top to press it to the soil.
Water for 15 minutes a day until the roots anchor back to the ground. You can check for root growth after two weeks by gently lifting a corner of one of sod sections to see if it's holding to the ground.