The purpose of a meeting is to gain results from a team of people that otherwise couldn’t be achieved without the meeting. The meeting is not a form of productivity for business tasks it can provide direction in which to drive work tasks.
Here is my list of simple meeting rules.
Publish an agenda with the meeting requests, a meeting can be rejected or ignored unless an agenda is published.
The agenda needs to specify the order of the conversations in the meeting, the subjects, who owns them, and how long they are to be discussed.
A meeting has to publish action points at the end of the meeting that need to be assigned to a person, with a finish date and delivery point. (this can include having another more restricted meeting with less staff later on!)
Publish results of the meeting. Minutes to the meeting should be published with in 24hrs day of the meeting. They should be short and concise with action points, who is taking them and when they should be delivered.