Too much water can overload the soil so that air cannot get to the roots, and can encourage plant diseases. Soil can absorb only so much moisture and the rest simply runs off. A timer will help, and either your kitchen timer or an alarm clock will do. Automatic sprinkler systems should be operated only when the demand on your town's water supply is lowest. Set the system to operate between four and six a.m. Don't scalp your lawn during hot weather.
Taller grass holds moisture better.
Learn what types of grass, shrubbery and plants do best in your area, and in which parts of your yard, and then plant accordingly. If you have a heavily shaded yard, no amount of water will make the roses bloom. In especially dry sections of the state, consider attractive arrangements of plants that like arid or semi-arid climates. You don't have to be a horticulturist to have an attractive yard, but do learn about the plants you have so that you can water just enough to keep them healthy, and not enough to waste water and injure the plants. Consider decorating areas of your yard with rocks, gravel, wood chips, or other materials which are now available and which require no water at all.