I've lived on both sides of the spectrum, having been raised in a very strict Catholic household, and passing through a gamut of phases--Protestantism, Deism, Buddhism, and then finally Atheism. I understand the argument from the religious side. I understand the argument from the atheist side. And I think this, more than anything, is what people need--empathy. Try to see it from the other person's point of view before you begin debating or discussing it with them. Regardless of how much you agree or disagree with someone, remember their basic, integral humanity.
Here, for me, is one of the disturbing, frightening things I have found in a poll (Pew Research I believe, not sure of which date, I don't have the citation)--that atheists are placed lower on the trustworthy scale than Islamic Fundamentalists and pedophile priests by the general U.S. population. I have different ideas on why this is so, but mostly I tend to think it is because the majority of the U.S. is religious, and if you go deep enough into a person's psyche, I think that a perceived attack on a god in one religion is an attack on any god...in other words, religion makes strange bedfellows as much as politics, and in one light, an American Christian has more in common with a Muslim from Iran than an American atheist.
I've been asked that, without a belief in God, how can I have any morality? This kind of monolithic, arrogant thinking runs the same course as basic racism, sexism, and other -isms--if you're not like me, you must be wrong; not only wrong, but evil. It might be coined the Golden Rule from the Bible's version of it, but the precept of treating others with respect is universal to the human condition--the hard part is applying it at all times, even if you don't agree or like someone else.