Business Insider asked an etiquette expert what people should avoid doing at high-end restaurants. She said diners should never disregard the waitstaff or arrive late to their reservation.

And a reminder, if you're visiting any restaurant regularly, make sure you sign up for a rewards membership. If you're already spending money there, why not take advantage of extra savings? From March ...

d3sign / Getty Images A restaurant can measure success through customer return visits and reviews from local media. Seven key ratios can help measure financial profits and ongoing costs and revenues.