Almost always when someone orders a refresher I ask if they would like it with lemonade or without, a decent amount say with.

For chais I ask if they would like vanilla chai or just regular chai

After they order drinks I’ll ask if they would like anything to eat

That’s all I got

When people ask what my favorite drink is it’s usually something with mods like iced chai with chestnut praline soy milk shot of espresso and sccf

A big one I notice is that customers don’t always know we have a Trenta size so they don’t know to order it so I usually say “Did you want to upgrade that to a Trenta/bigger size for 50¢ more?” And those add up pretty quick, especially in the summertime

I find that simple language choice helps a lot. “Is that all for today?” just kinda ends the order, but “What else can I get for you?” at least makes them think about if they want something more.