"The best chance of getting them to a church is when someone they know and trust invites them, offers to accompany them, and there is reason to believe that the church event will address one of the issues or needs they are struggling with at that moment."
How do you learn what issue that person is struggling with? Say "Welcome" and listen to them!
How about help with reaching the intermittent or "under-churched." The under-churched group must contain persons on a spiritual quest or those struggling with an issue. Say "Hey, we've missed you" and then listen to them!