[Callers] Crowd noise during walk through

Hello, I'm a new caller and have been noticing recently at some dances that the crowd is quite chatty and noisy and it can take a long time to get them to settle down and listen to the walk through. And then even during the walk-through the noise level rises again so that some people in the hall can't hear the walk through. I'll be calling my first full evening next month at a venue that is known for the chattiness of the dancers. I want people to be able to socialize but I also want dancers to be able to hear the entire walkthrough. Can you give me some tips on how to balance socializing (i.e. how to judge when to start) and ways to regain their attention mid-walk through without sounding like a schoolmarm or raising my voice? Thanks much! Jacqui