You might have the best of ideas or the most amazing insights, but it is of no use if the people you are talking to are not listening to you.
Some say there is a science to it, some say its your posture that demands the respect and some merely believe that it is your role/age that gives you the edge. However, the real solution is that it is all in your own hands, how you deal with your audience is what makes them want to hear what you have to say.
This beautiful article on Mashable explains the basics which can resolve any issues you might be having and that too in a very simple manner;