I live in America and am surrounded by religious people of all stripes -- I was an Atheist Pagan for many years -- and when someone gets to spouting what they believe or talking up some kind of woo, I listen, acknowledge it politely and then say "And I don't," or "And I can't feel energy. Never been able to."
That usually brings a person to a dead stop and sometimes leaves them a bit stunned. After that, connections generally fade and they stop coming around.

"I'm an atheist" When their face calms down from the slightly shocked and puzzled look you get, the message then reaches their brain and immediately it starts "Are you sure? How did this happen to you? etc" I simply reply "I'm not just an atheist, but a militant atheist and there is nothing you can do or say that could change my position on this, but if you like I can tell you why I am...." I normally never get to the "let me tell you why" part!!!

If the subject comes up, I just say that I am an atheist. I live in what is referred to as the South Bay, about 50 miles from San Francisco. People are pretty cool with it here. I don't know how I would be in, say, Virginia, where a friend of mine was hounded out of a job because her coworkers found out that she was an atheist.

If they ask me what religion I am or what I believe, I say that I’m atheist. I might add that I live in a small extremely religious town and at the present time I'm about the only nonbeliever here that I know of. I haven't had much blow-back.

Religion (or lack of religion) is personal. I do not generally talk about it. If someone specifically asks I say I am non religious and then drop the subject.

I tell theists, I don't think there is a God, but if there is, he knows I'm telling the truth. And I am perfectly willing to listen to God, but not hearsay about God ! Did God tell you he authorized a book, or do you normally go around talking crap about the creator of the universe ?

I don't !

Generally, the brainwashed have a hard time with anyone who does not share their delusion and will most likely become offended regardless. If I know the person I try to be courteous but any stranger knocking at my door is told that I'm an adult in the 21st century and have no reason to believe in any superstitious nonsense.

I say I don't know what is true and until then I wonder. That is what I say.

I tell them I'm not a religious person, and tell them why.

At some point the conversation gets to some mention of heaven or god or something along those lines and I say that we should be talking about things that are real and not imaginary.

I keep my mouth shut, until they start to talk about their faith. Then as far as I am concerned it is OK to go into great detail why there is no god and their belief is a delusion.

I've never had to tell a religious person that I don't believe in a God. For example, if I'm at their house for dinner and they say a prayer over the meal, I just bow my head and let them have their ceremony. No problem for me, no threat to me,

I don't believe in numble-jumble nonsense. That usually shut them up, hahaha!

I try not to. If I have to, I just tell them that I'm not religious. It prevents pointless argument.

When a conversation turns religious I most always say that I am an atheist. That almost always ends the subject and the conversation turns to another subject.

all of my wife's family are very religious so I pretty much keep it to myself, if any one were to ask I would not deny it though

if asked i say i am an atheist
but i don't go round shouting about it
i don't like the godsquads preaching at me so why would i do it
if you have a mind decide for yourself

When a conversation turns to this subject, I always just say that I am a devout atheist, and the subject usually gets abruptly changed.

I just let them know if they bring up religion.

Whenever it seems appropriate or necessary, I tell people simply that I am an atheist. If they want to pursue that for whatever reason, I will engage them. I am who I am and if other folks can't deal with it, it's not my problem.

Unless it comes up, I don't. Have been known to hedge by saying "I;m not Christian". Being braver now and just saying "atheist" if they're trying to push a religious identity on me.

It's dangerous in my country to say that

I'm straight forward about me being atheist but I don't bring up religion, unless someone else starts it. I'm respectful about it and will talk about it, but I do tell tell them if they ask me.

That kind of depends how the subject comes up. If we seem to be hitting things off and I think they should know where I stand, I just calmly tell them my stance on belief and hope for the best. If they're constantly talking about their religious views, or start off with religious rhetoric from the moment we meet, then I'll just tell them right out that I don't believe in any of it, and as long as they don't push it on me, we're cool, but if they do, I'm out.