And never dress as if the jeans had been switched out from formal suit pants at the last minute: No fancy French-cuffed shirts with jeans, he advises.

A blouse you normally wear with jeans will look good with shorts for an alfresco lunch.

Eric Brewer, a video producer in Washington, D.C., recently wore a dark denim jacket with a slightly lighter faded pair of jeans, paired with a black shirt, and plaid scarf to a party.