I think one of the absolute important things to do is to listen first. Hear what they know, what they've misunderstood, and what had no idea about. Some know a lot about the faith but just haven't arrived to it yet. Others know absolutely nothing about it. And some think they know everything about it but have a perverted interpretation of it. If we first listen, we can better evangelize, not make any assumptions which might insult their intelligence, and even establish a trust within the conversation, because let's face it, a lot of people would trust Christians last.