Post stakes along the outer edge of the area that you will be planting. Tie string to the stakes to form a border. This will let people know that you are planting in the area and not to walk on the lawn.
Apply fertilizer to the soil of the lawn and allow it to set for two to three days. Water each day to help the fertilizer soak in and amend the soil, readying it for seeding. There are many lawn fertilizing products available commercially or you can use homemade compost.
Fill the seed spreader and spread the seed in rows across the lawn. Seed should be spread thickly because birds will eat some, and some will simply not sprout. To avoid bald patches, grass seed needs to sprout evenly across the lawn.
Spread straw in a thick layer over all the grass seed. Straw helps protect the seeds and retain moisture.
Water the area that you have planted daily. Watering in the morning is preferable because the water will be absorbed throughout the day, and the sun will warm the water as well as create underneath the straw a steamy and damp area perfect for your grass seed to sprout. You should see small new blades of grass popping through the straw in about 14 days.