There is an art to effective meetings, and just scheduling a bunch of people to show up is not it.
Consider for instance the number of participants:
Seven is the magic number for business meetings. Each additional person cuts decision-making by 10%, according to Quartz.
Also, state purpose clearly and reduce time allocation to a minimum.
This is pretty basic, but the abundant horror stories of regular time-suck events at both big and small organizations indicate that the points bear repeating.