This is the best time of year to start a new lawn and/or overseed your lawn.
Dethatch using a power rake, tow-behind dethatcher, or dethatching rake.
Core aerate by doing a double-pass – up/down then left/right or north/south and east/west.
Mow low around 2 – 2.5″.
Overseed or slice seed with quality grass seed. You should aim for 3 lbs. per 1,000 feet.
Fertilize with a quality starter fertilizer.