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.
“My luck at the gambling table was varied; sometimes I was fifty to a hundred dollars ahead, and at other times I had to borrow money from my fellow workmen to settle my room rent and pay for my meals.”
“It's hard to know whether certain characters come to life or not, they either come to have their own life or they don't. I've written many things in which the characters just remain inert.”