DO: Follow your hosts’ cues. A pile of shoes by the front door means you should take yours off too. If your hosts say grace before meals you’re not obliged to join in, but wait until their prayer is concluded before taking a bite. And if there are young children in the household, follow their parents’ lead about what’s allowed in terms of behavior, food and bedtime — and, yes, that even applies to you, grandparents. DON’T: Offer your unsolicited opinions about the house rules.