A great way to learn is to have several people explain a concept to you.
An even better way to learn is to explain a concept to someone else.
Much more better is to have to explain the concept to someone in a different way than you did the first time.
There’s a difference between looking like you know what you’re doing, and knowing what you’re doing. But most of the time, if you really do know what you’re doing, you’ll look like it.
One of the best ways to sound smart is to try not to sound smart. Simplify, address the matter at hand, and approach concepts in a step-by-step way, without a lot of needless jargon or overcomplication. (Incidentally, this is a great way to be smart, too.)
Successfulness is not judged by self-esteem or personal knowledge. It’s judged by your effect on others.