I think its important to realize that conversion doesn’t come over the course of one argument. It’s a slow process, and the reasoning has to happen within that persons own mind over an extended period of time. You’re asking someone to turn their world view upside down- be patient.
All arguments are good, both altruistic and moral, both theoretical and emperical. Generally I think people will want to have an understanding of the entire picture before seriously considering it. I myself became a libertarian for altruistic reasons, but have gradually changed to a more moral stand point since.
Most importantly: Be a role model. Always stay calm and civil, and never steam-roll anyone. Avoid putting people in a closed defensive position. Do what you can to live morally and to be sucessful. Peoples views are heavily effected by the people in their presence they look up too – do the best you can to be one of those people.
I love to look at videos of Milton Friedman for his amazing charisma and persuasive argumentation. Although I know his views on money and altruism are a bit problematic, I think his style is very admireable.
ps. I’m comitted to the long term project of turning my dad from a environmentalist, highly academical, social democrat into a libertarian. It’s a very slow process, but it moves steadily forward. I sent him a link the other day to a video of a speech by Dr. Woods himself. At first he shot it down as just shallow rethorics, but a week later he called me an said he had been thinking about it the whole week, and that he was considering ordering Meltdown. For every time I meet him and discuss these issues, he is willing to admit that a few more bad things about the government and a few more good things about the market.