To ask them (especially with card machines) how much of it they personally get. If you like to tip for exceptional service when you eat out, due to the recent change in the law regarding tips please ask your server if they actually get a decent amount of the money you leave. I'm not here for a debate, I simply want people to know that some companies are distributing it evenly between all staff - which to be honest is grossly unfair when managers and chefs aren't the ones on minimum wage 🙂