1. Salty snacks at the bar Those complimentary pretzels and peanuts weren't set in front of you as a kind gesture. They're there so you'll order more drinks. Salty snacks make you thirsty. End of story.
2. Menu design Our eyes have a natural tendency to look at the right side of the menu first, so restaurants usually list their most expensive dishes in that area. Some restaurants put their most expensive items at the top of the menu, so other items look more reasonably priced. Shaded boxes and borders around menu items also attract hungry patrons and can increase sales.
3. Lack of dollar signs Have you noticed that more restaurants are listing prices without dollar signs? That's no coincidence. In a Cornell University study, guests given a menu with only numbers and no dollar signs spent significantly more than those who received a menu with prices either showing dollar signs or written out in words.
4. Flowery descriptions Which sounds better: "Classic Burger" or "Tavern-Style Burger with Frizzled Onions and Smoky Barbecue Sauce"? According to a six-week field experiment by Cornell (.pdf file), menus that had descriptive or creative food descriptions, rather than items with simple names, increased sales by 27%. To add insult to injury, scrumptiously described dishes often cost more.
5. Extremely friendly servers Customers leave higher tips when their servers personally introduce themselves, crouch beside the table, or ask about your day.
6. The upsell The servers who grip your wallet with their charisma also pull you in with the classic upsell, and they're very good at it.
7. Music Classical music makes you spend. According to the Daily Mail, University of Leicester researchers found that classical music, associated with affluence, encouraged spending at restaurants, while a lack of music caused diners to spend drastically less.