• Rake the area to remove leaves, sticks and other debris.
• By hand, sprinkle the area with fresh topsoil, filling in any low spots as you go.
• By hand or by using a spreader, apply seed. Make sure you choose "shade" or "sun" seed according to the conditions. Mixed "shade/sun" seeds won't usually survive in shady areas.
• By hand or by using a spreader, apply slow-release fertilizer or a natural fertilizer.
• Some fertilizers also contain chemicals designed to kill broad leaf weeds like dandelions.
• By hand, sprinkle the area with some more fresh topsoil. This helps hold the seed in place, protect the seed from birds, and feed the seedlings.

If you want a professional to renovate the lawn:

Professionals are likely to follow a similar procedure, although with more powerful equipment. More sophisticated equipment allows them to complete the work in much less time.

They may also address:

Soil Testing

Using an on-the-spot soil analysis kit or by sending a soil sample to a local lab, they may be able to determine that the soil needs additional help. Quite often, it is determined that the soil needs more lime.

Aeration

The soil below the grass tends to get compacted over time. The tightly packed soil is inhospitable to worms and other symbiotic life forms and makes the grass more vulnerable to drought. The professional will use a large machine that pulls hundreds or thousands of small dirt plugs from the ground, loosening up the soil in the process.

Pest Problems

In the course of doing the other work, it is likely that a professional would notice if lawn-hostile pests are present. They can choose the most appropriate remedy.

Watering

Water daily for 10 to 14 days. Do not water so much that puddles form and water begins to run off. Besides washing the seed away, excessive watering will carry the fertilizers to nearby rivers and streams where it can harm wildlife.

by David Hollies, reprinted courtesy of HomeAdvisor.com