The generally recommended mowing height is 2.5 to 3 inches. Grass that is mowed any lower may cause unnecessary stress on the lawn and allows insects, weeds and diseases to gain a foothold.
Improper mowing techniques are "a primary cause for the decline of home lawns and are just as important for a young lawn as for an established lawn." The basics are the same for both types of lawn.
A sharp blade is essential. Make sure that the mower blade has been sharpened for the season. They also suggest to avoid cutting grass if the air temperature is above 90 degrees.
Finally, the most important fact is mowing height. DO NOT CUT THE GRASS TOO SHORT. Most grasses in our area should be mowed no lower than 2 inches, but 2.5 to 3 inches is actually preferable. Low mowing heights allows weeds to get a foothold, particularly in a newly established lawn.
We have always advocated taller mowing heights as causing less stress on a lawn. Correct mowing is an extremely important basic cultural practice.