A few suggestions on speaking to people about gay issues

Important points on both sides of the issue deserve our attention. Take the discussion here with you to the dinner table, the church gathering, the movie night, and the water cooler. You don't have to be confrontational. You don't even have to voice your disagreement. Raise the subject and then ask people questions about their beliefs and opinions. Don't be sarcastic, don't be ironic. Ask questions you really want to know the answer to. When people see that you're open to understanding them and possibly agreeing with them, they'll reciprocate.
Don't waste time preaching to the choir. Think of someone you disagree with, find common ground and build your foundation on that ground. If things start to get nasty in a discussion, move back. Say things like "We don't have to talk about this," and, "I don't want to upset you." Let anyone who gets upset in a discussion know that you care more about them than about being right. Apologize if you have to.
My personal approach to this issue is based on the idea that our movement won't work if it is all about which side can be louder, more emotional, or more dramatic. Logic and reason linger much longer than the anger and revulsion people feel when they're first confronted with the possibility that they're wrong. Work on keeping calm during a discussion and you'll be more effective.
Don't waste your time hounding someone who doesn't want to talk or listen. My experience is that most people are thoughtful and want to understand. But some people can't be reached. If someone seems too afraid, or if they are hell-bent on being a victim, move on. Some people are more oppressed by their own fears and beliefs than gays are by the government or the church. Let those people go, or you'll find yourself trapped with them in their web of guilt.
Most importantly, LISTEN! Listen to what people are saying and think about it. Always accept that you might be wrong. I love writing down arguments I hear and formulating a reasoned and well-thought response. Think critically about your own positions and consider how new ideas and arguments factor into your stance. If you hear a good argument, write it down and craft a written response (Avoid giving people written responses to their thoughts and beliefs - they tend not to receive this sort of gesture well). Instead, mull over your response and bring it up the next time you find a window. In the mean time, post it here - even if you disagree! Your well-articulated thoughts and responses can help others inject more substance in their daily discussions. Even if we disagree, I hope you'll join me in promoting a more substantive dialogue.