Planting grass seed to create a lush healthy lawn is best done in the spring or early fall, and it is important to understand how to do it properly or you could end up with a lawn with still no grass and wasted time. Although it is less work and money then laying sod on a yard, it still requires preparation and patience. The key thing to remember when planting grass seed properly is to prepare the soil correctly, and to protect the seed after applying it.
Loosen up the soil in your yard and remove any large obstructions before planting any grass seed. Do this with a rake, going over any area you want to plant grass seed. You want to loosen up the soil about 2 inches deep, removing any rocks or stray plant roots in the process and discarding them. After you have loosened up the soil, run the rake over it a couple more times to make the ground as even as possible.
Layer the seed over the ground evenly. Start at one end of the yard, and sprinkle it back and forth all the way to the other end. After you lay down the grass seed, use the rake one more time over the entire area to distribute the seed evenly and to integrate it into the soil.
Spread a layer of straw on top of the grass seed and soil, for protection from birds, strong winds and for insulation for the grass seed to germinate.
Water your lawn immediately after finishing up with the straw layer, either with an irrigation system or a sprinkler. Water it for about 10 minutes, then let the inch or so of water seep in. Then water it for another 10 minutes. You want the water to penetrate about 6 inches deep for this first watering, but also make sure you don't puddle the water as it will wash the seeds away. After this, water the grass seed on the lawn twice a day for the first two weeks: once in the morning, then again in the afternoon.
Watch for the grass seed to sprout. Once it does, water the yard only once a day. The next week, water it every other day. The week after that, water it three times a week, and so forth.