Here is the method that has worked with me in just about every area of my life when it comes to introducing Ron Paul.
I'm subtle and at no time to I just go off the rail. I usually wait for the to mention something political or a topic that I can make a mention about how bad our politicians are. Then over the course of several conversations it could be days or weeks depending on how much I told to the person. I will identify with what ever there political presuasion is. A good line for me is something like, "I can totally see why you feel that way". If they are pro Obama, Newt, or anyone else, I try to be well informed enough to point out something they have said or done that I like (that can be tought). Almost right way I start planting doubt with their candidate and they don't always realize it. I may say something like I just wish Newt, wouldn't have had such a crappy personal life. I mean the guy is intelligent in did some good things the last time he was in office but if you look at his private business life and his private personal life that's just frustrating cause it's not admirable qualities that you want to see in a president.
At this point I have not told them anything about Dr. Paul, nor have I aligned myself with anything other than there beliefs. I may start saying stuff like what happened to the "honest politicians" the ones whose history in office actually matches the promises they have made. So I will start seeding concepts and charaters about Dr. Paul. Now mind you this can be in any area that I feel they will agree with me. Such as limited government, integrity in politics, economics, foreign policy, etc. I steer the conversation to a place where I have them agreeing with me about a politician that is like the fantasy politician we are talking about. Then a few conversations later after we have identified really really well with each other and the type of candidate we want. I may say something like, "You know we have been talking about finding the person that could be a honest politician. You know someone who believes in small government and really means it. Some who can stand up to political pressures from those big donors and special interests. You arent going to believe this I think I may have found our guy.
Of course they are like "Who Who". With a pokerface and not showing all my cards I say, "you aren't going to believe this for a long time I thought this guy was alittle quirky but the more I have started to read on him the more I like him". They are still wanting to know who it is. So I give myself a way out if I have to back pedal and bring him up another way I say, "I don't know what you are going to think of this but it's that Ron Paul guy"
Now this is where I have seen most Ron Paul supporters mess up. What happens more than half the time is it starts a discussion. And they say something like yeah but what about his foreign policy or his stance on Israel. I DO NOT start discussing it and debating it with them. I just say well I don't know those are good questions give me your email address I can send you some of the videos and stuff that I have watched that discusses some of that and then I send my favorite youtube videos on the topic. I let the videos do the convertingI have found very passionate Ron Paul donating converts this way. Its great to see them on facebook now liking my videos, and openly discussing Dr. Paul. It's a slower subtle approach but has worked well for me.