Set the blade height on the mower so that only one-third of the grass blade will be removed. Determine the average height of the overgrown grass and divide by three to determine the cutting height.
Start the mower following the manufacturer's recommendations. Cut the grass with the mower in a back and forth direction across the lawn.
Allow the grass to recover from the first cutting for one day.
Lower the cutting blade by another third when cutting very overgrown grass. Cut the lawn in a back and forth direction that is at a right angle to the first cutting. Allow another day for the grass to recover.
Set the blade height to the normal setting and cut the lawn once again. Cut the lawn in a back and forth direction that is different than that used on previous cuts. Consider a diagonal angle for cutting.