You can dabble in some varied combination ... than a regular business suit. Then add a knit polo, which is smarter than a T-shirt (definitely no T-shirts in the interview), but still easygoing.

Wear a white or pale-blue business shirt and a grenadine tie. Try to keep the knot as neat and un-chunky as possible. A four-in-hand would do the trick. You can wear low-key cufflinks—provided your ...