One of the biggest sources of distraction has to do with something every meeting room has and that is a door. Doors squeak, they slam shut, and they allow people to walk in the audience's line of sight. According to Tom's Law of Presentations, these three things are only allowed to happen at the exact moment of your best punch line or most dramatic statement.
Doors are very easy to deal with if you can gain access to the room early. The first thing I do is check to see if the doors squeak. If they do, I call maintenance or find a little oil can and oil the hinges. If it's an old hotel, this probably hasn't been done in 30 or 40 years. Then I let the door swing shut on its own. This tests the closing mechanism. If it is hopelessly weak and allows the door to slam shut, I either ask for it to be adjusted (which no one ever knows how to do) or I have someone stand at the door to open and close it for latecomers. The latch of the door can make lots of noise to, so you simply tape the catch mechanism shut.
Door location can also be a pesky problem. Sometimes the room is set so there is a door behind or very close to the stage area. If someone would enter this door during your presentation, it would be very distracting.
You can usually tape up a "Please Use Other Door" sign to help with this. When you know you have any kind of door problem, try to alert the planner or recruit people from the organization to police the doors for you.