Actually, having a beautiful lawn isn't much of a secret at all. Here's how it works:
1. Plant the right type of grass for your area
2. Use the proper fertilizer as directed a couple of times a year
3. Keep well watered during the growing season
4. Never mow shorter than 1/3rd the present height
Select grass seeds that grow well in your area.
Being a native Southern Californian, I was very partial to a Dichondra lawn. Imagine my surprise upon moving to Oregon to learn it simply wasn't possible to have a Dichondra lawn in Oregon due to the colder winters. Plants and seeds are available by catalog according to the zone you live in.
In order to have a lush, healthy lawn you are going to have to feed it with the proper nutrients. You will find the right fertilizer for your lawn at your local garden store. Follow the simple directions and you are good to go. Fertilizer is available in both liquid and dry form. I have had good luck with both. A word of caution. When it comes to fertilizer, more is NOT better. At best, over fertilizing will burn your lawn.
As to how much water your lawn needs varies somewhat depending on grass type. In general, applying one inch of water per week is the recommendation when there is insufficient rainfall during summer drought. An inch of water can be measured by marking the side of a tuna or pet food can placed in the lawn. The best time of day to water your lawn is in the early morning hours. If using a timer, try setting it for 2 hours a day, 3 days a week or every other day.
For a healthy lawn, never cut more than one-third of the grass blade in any one mowing. If the grass gets ahead of you because of a busy schedule, move up the cutting height of your mower to the highest setting. Catch the cuttings with a bagging unit, rake the lawn with a leaf rake, or use a mulching blade. Then move the cutting height back to normal and cut the lawn again a few days later.
For more information on planting and maintaining a beautiful lawn, look for a good book on the subject in your local garden supply store.