You want a pretty lawn, so your neighbors won't talk about you. (They will anyway, but let's continue.) But you hate all the watering, fertilizing, and disease and weed control that producing one requires. So I'm going to give you an easy out -- the single, best way to produce that thick, green carpet your neighbors will resent AND decrease your effort at the same time.
Cut your lawn high. (No, I don't mean mow under the influence of a substance that makes you crave Raisinets and listen to "Stairway To Heaven" on your noise-canceling earphones for five solid hours.) Put another way, stop cutting your lawn too low. Grass hates to be scalped, but the weeds love it. Scalp your lawn on a routine basis and you'll end up with nothing but weeds.
During the hot summer we're now entering, it's especially important not to cut your grass -- no matter what kind you have -- any shorter than two inches. This is because grass blades make food for the roots to grow. Scalp a lawn in hot weather and its roots essentially stop growing. The scalped lawn can't cope with our typical summer droughts, so it turns a nice, crispy brown. You, naturally, respond by watering to turn it green and make it grow so you can scalp it once more and turn it brown so you can water it to turn it green again, ad infinitum. Nothing, outside a Mount Kiluaea lava flow, is more stressful to a nice lawn than quick grow-no grow cycles.
So stop scalping. Two inches are the minimum in summer. For some grasses, such as St. Augustine, Kentucky bluegrass, and tall fescue, set the mowing height to three inches. By doing this, you'll find your grass stays much greener for much longer during dry weather. You won't have to water as often and the taller grass blades will shade the weeds, making them less competitive.
And while we're talking about mowing, please, please, PLEASE use a recycling mulching mower and don't bag your clippings. When you bag and throw away clippings, you're essentially bagging and tossing out the $30 bag of fertilizer you applied in spring. Returning the finely chopped blades to the lawn adds organic matter and nutrients, meaning you'll need a lot less fertilizer in the future.