The meeting should start on time with all necessary meeting materials available. If you are using AV equipment make sure before starting the meeting that all equipment is working, and cued up for use. For instance make sure to log on your computer, get network access if necessary, and cue up videos, etc. This will require that you arrive before the start of the meeting time.
Post the agenda or have paper copies available for participants.
Make sure that all who attend feel welcome.
Take time to introduce the participants if they do not know one another. Name tags or tent cards could be useful if it is a meeting where all are new to each other.
Take time to orient participants to the surroundings if it is an unfamiliar meeting location. Items such as bathroom location, water, phone, etc., need to be identified.
Take time to agree upon meeting guidelines for working together. You can either bring a pre developed set of guidelines for discussion or generate the guidelines with the group. Either way, all group participants need to agree and adopt the guidelines. When adopted the guidelines should be posted in the room or on the agenda for all meetings.