It's a mix somewhere between being bartender and therapist. You listen a lot. You learn their food and drink preferernces and provide creature comforts accordingly. You are sympathetic, enthusiastic, sometimes conspiritorial. When they start crashing out on the sofa a lot, leaving earlier, coming in later, you know you've won their trust. You can only then practice your craft to the fullest, winning the things you want, cutting out the stuff you hate, because trusting you means that they will listen to you and value your contribution. Otherwise, you're just an operator pushing the buttons for them.
In other words, it's the whole human side of the business away from the tech stuff. Equally as important though if you are to build a reputation and keep them coming back for more.