Cut around the damaged areas with a spade shovel at least two inches deep. Slide the spade into the cut and shovel out approximately 2 inches by sliding the shovel under the sod.
Fill in the area with fresh high-quality topsoil. Lightly tamp the soil down with a metal tamper to avoid settling later. Add additional soil and tamp until the soil level remains at the same level as the ground around the repaired area.
Spread grass seed over the fresh dirt. Overlap the new seed into the grass covered area to help blend in the patch. If you are not sure what type of grass seed to get, take a few clipping to the store with you. A qualified sales rep can help you determine the type of grass.
Cover the seed with a small amount of hay straw to prevent birds from picking the seed out of the dirt. After the seed germinates, you can remove the straw.
Water the seed per the instructions on the packaging. This will differ depending on your region, temperature, time of year and brand of seed.