This gives your lawn a healthier root system. If the grass gets too high, mow over clippings a second time to further shred them, or raise mower height and gradually lower it over a span of several mowings. Cut grass when it is dry. Avoid mowing wet grass, since wet clippings mat together. Use a sharp mower blade.
Dull mowers use more gasoline and can give the lawn a frayed appearance.
Generally, mower blades should be sharpened every year. Simply remove the grass catcher. Kits are available to convert some bagging mowers into mulching mowers. Aerating your lawn once a year will open up the soil and permit greater movement of water, nutrients, and air. This makes the grass clippings decompose faster.