To prevent crowds from getting out of control:
Ensure clear information is provided before any activities start.
Provide clear and regular messages or updates so people know how long they will have to wait.
Work closely with community leaders to organise people into small groups.
Ensure sufficient crowd control personnel.
Ensure there are facilities (shade, water, latrines, etc.), especially in settings where people are expected to wait for several hours.
Ensure sufficient communication equipment (e.g., loudspeakers.