When Julia Roberts asks for dining-etiquette tips before a big night out with Richard Gere in Pretty Woman, who doesn’t sympathize? Even if you’ve mastered which fork to use, there’s still the sometimes awkward question of when to pick it up. Letitia Baldrige, author of Letitia Baldrige’s New Manners for New Times (Scribner, $35, www.amazon.com), weighs in on the right time to start eating in social situations.

At a seated dinner, always wait for the host to begin. (If she’s engrossed in conversation and forgets to give the signal to start, “jokingly say, ‘Sarah, there are people starving here,’” Baldrige suggests.)

At a buffet, if you’re the first to arrive at the table with your food, it’s polite to wait five minutes for a few others to join you — “unless there’s hot soup, in which case consume it immediately!”

If tables aren’t provided and you’re balancing a plate on your knee, feel free to dig right in.

In restaurants the host again takes the lead. If you’re going Dutch treat, it doesn’t matter who starts, though “it adds a note of civility if the table defers to an older person present,” Baldrige says. In either case, it’s polite to wait until everyone is served.

On a date, “if a man wants to be chivalrous, he will wait for his companion to begin,” says Baldrige. “If he is the average man today,” she adds with a laugh, “he won’t understand what chivalry entails, so just start.” Of course, don’t judge your guy solely on this. You never know — he could just be really hungry.