Regarding people who seem to be wiser, wittier and more convincing than others: are they really closer to "the truth", or is it just the case that they just happen to be louder than the rest? Or maybe they have an unrelated personal trait that makes people listen to them more readily, regardless of the validity of their thoughts?
Maybe these people just happen to have some personal charisma. Maybe it's the tone of their voice, or maybe it's their body language. It almost surely has to do with seeing the person talk. I guess they display a strong belief in what they are saying by looking very decisive.
Yes, decisiveness in the way you present yourself is clearly the key to getting heard. Confidence is, of course, strongly related to decisiveness.