Well, my brother is someone I'm currently trying to win over, and he's one of those "I'll vote for Giulianni if he wins the primary" voters.
One thing that DOES NOT WORK is saying "we need to get respect from the world community". He doesn't care about that, because a lot of times the thing that made America great was doing things that flew in the face of the world community.
Show your Rudy fans that even if they were for going into Iraq, do they really think we need to go to Iran? If they say "yes, because Iran has NOOK YOO LER WEAPONS and an Islamo facist dictator," kindly point out that Pakistan has Nuclear weapons and is still giving harbor to AlQuaeda, and Saudi Arabia has Sharia Law.
Then point out that we consider these countries allies and that we just sent 10 billion dollars in aid to Pakistan.
Then point out that we used to consider Osama Bin Laden and Sadam Hussein "allies" and we gave them aid and weapons.
Then say something like this: "Look, I understand that we were all frustrated after 9/11, but if you want to stop terrorist attacks in this country, would you rather have the National Guard on the border of Iraq and Syria, or Arizona and Mexico?"
Then take that right into the amnesty discussion, or the weak dollar, or whatever else you think would be a key issue. Show them that maybe the war isn't the best idea, and then hit them with a policy they would agree with Dr. Paul on. Most Republicans/Conservatives I've found never gave him a chance because of the war stance. But when you show WHY he takes that stance, they might find they actually agree with him!
It's not too difficult if you know the person you're talking to. Ron Paul's message is for everyone, and there are many parts of it every American can agree on. My brother has now said he wants to find out more about Ron Paul, and definitely WILL NOT vote for Giulianni, even if he gets the nomination.