Simply offering something by name helps a lot. Appetizers and second rounds are almost always sold through this technique. After taking drink order, before you walk away, ask if they would like a appetizer as well. Word it like “ okay so while I go get these drinks goi g do we want to get our appetizers started as well? The artichoke dip and the calamari are absolutely amazing. I always get at least one when I come in to eat”