Have sufficient breaks between sessions
It can be hard to get around quickly – longer breaks in your schedule means everyone is more comfortable.
If you’re running long sessions, people will want to move around in the breaks. They might be going to the bathroom, or to get a drink, or going to a different room if it’s a multi-track conference.
Particularly in a large venue, it can be difficult for people to get around quickly. Maybe you have a wheelchair, or a child, or a foot injury, or you’re talking to somebody about the session that just finished.
Make sure you plan sufficient breaks between each session. People won’t be rushing around the building to get to talks, and your speakers will be less distracted by late arrivals.