If your lawn is very uneven, you can roll the lawn first thing in the spring when the soil is still moist. The next best time to do this is in the fall. The key is to use a light roller. Heavy rolling on wet, heavy clay soils can cause harmful soil compaction. It is not generally recommended to roll a new seedbed, since the new seedlings will take root easier in loose soil. Simply use a garden rake to level the soil. Please remember that this is only necessary if the soil is uneven.
If the problem is severe, take a look at our step-by-step project for grading your lawn.