What convinces is conviction. Believe in the argument you're advancing. If you don't you're as good as dead. The other person will sense that something isn't there, and no chain of reasoning, no matter how logical or elegant or brilliant, will win your case for you.
“It's just about going out and getting the shot, so I have a great understanding of how to execute it, so that really helps me, and also having a good understanding of all the action that I'm shooting, it helps me in determining how I'm going to capture it.”
“Do not expect the world to look bright, if you habitually wear gray-brown glasses.”