1. No set time limit for the meeting.

Weekly staff meetings also don’t have to last 60 minutes. If they do, you either have too many people in the room or one person with enough hot air to make up for everyone else.
Set a limit. Try 30 minutes. If you need more that, it could be a sign you’re relying too heavily on staff meetings to get information. Maybe you need to remove your middle-aged spread from the bottom of the chair more often during the week and conduct more management by wandering around.
2. No agenda.

Kinda like the butterfly effect, no?
A fixed agenda, sent out 24 hours before the meeting, symbolizes your commitment to getting the important stuff done without wasting the staff’s productivity time. It gives the introverts in your department time to mull over what will be covered so that they can contribute to their highest level. And it keeps things on schedule (see #1).