Mow the grass short
Remove rocks, sticks, and debris
Mark low and high spots
Fill low spots with topsoil or sand-soil mix
Use a rake to spread the fill evenly
Press or tamp the soil lightly
Water the area to help it settle
Add more fill if needed after settling
Topdress the lawn with a thin layer of compost or soil
Level the surface with a lawn leveling rake
Overseed bare or thin areas
Water regularly until established
Repeat small adjustments as needed