Mow the lawn short
Rake away dead grass, thatch, and debris
Test the soil if needed
Apply a starter fertilizer if appropriate
Loosen the top layer of soil with a rake or aerator
Choose grass seed suited to your lawn and climate
Spread seed evenly over the lawn
Lightly rake the seed into the soil
Press seed into the soil with a roller or by walking over it
Apply a thin layer of compost or topsoil if needed
Water lightly and frequently to keep the seedbed moist
Keep foot traffic off the lawn until the grass establishes
Mow new grass only after it reaches the proper height
Continue normal watering and fertilizing as the lawn fills in