There is a thing called the Primacy Effect which is a psychological phenomenon associated with memory that says that items at the beginning (primacy) of a list or string of information are more easily recalled than items in the middle. That's why it's vital to start every meeting or presentation with something that drives intrigue. Nature has given speakers a gift in the first 5 minutes where what he or she introduces is more likely to be remembered.
Most people don't use it.
Don't open your talk with procedural information if you can avoid it. Start with something evocative. Even if you are just running a status meeting you could start by saying that the team is 15% ahead of schedule...or 15% behind. Start with a bang and then keep trying to introduce "moments of change" during your talk to maintain attention. Basically, with each moment of change you are resetting the listener's minds so that you get that instance of primacy again, and have 5 minutes of fresh attention. Use a story, question, move yourself, throw a ball, etc. to jar the viewer into a new mind set.
Robert is a speaker coach, actor, director, author, speaker, executive and overall marketing guy. He writes about all aspects of presenting and connecting with audiences.