A couple of sneaky ones that I always hated and refused to do.

When your guests are comfortably seated and you open the menu to hand it to them, open it at a page where the expensive stuff is so it's the first thing they see.

Make up an expensive, brightly coloured cocktail and just put it on a tray and walk around the restaurant a few times. People can be very “ see one, want one" with things like that. Do this on a busy Saturday night with lots of groups in ( especially women out with a group of friends) . One manager I worked with said this was successful for him about 80 percent of the time.

Bonus one. Wear earrings shaped like food., this was always kind of weird and amusing to me. I would wear these fake ruby like gemstone earrings, I would always sell more red wine. Swirly earrings that looked like pasta, more pasta dishes.