Start at the scheduled time. Don't, "give everybody a little time to join." You're just enabling shit behavior.

Never, ever ask, "who just joined?" when the join tone sounds on the call. If you need someone on the call, invite them, and address them directly by name. If you need to take roll, then call out names, one at a time. But don't do that either. Just do your meeting.

A meeting has a direct cost of the lost time of everyone on the call. Artificial delays for small talk or petty admin are a total waste of time and money. Keep it simple, on task, and as fast as possible.