I only bring it up if I am asked or if their is an activity I am being asked to join in that involves religion. When I do need to tell someone, I am straight up to them and try very hard to be positive and not show my self righteous indignation towards their beliefs.
I am sometimes asked to pray for someone. I tell them to pray for themselves. Sometimes, I see a look of frustration, sometimes confusion. I try not to get into the discussion. I'm not going to change anyone's mind.

I just say I'm not religious. Saves the confrontational judgment. In this culture, you're still judged as immoral if you don't believe in their myths. But, it is getting better. The younger generation seems to be more objective.

I bring it up with friends and answer fairly if they ask why. I think it’s important they have a good example of an out atheist to counteract the strawman and lies.

Good luck

Tell me who the eye witnesses were. How long after Jesus was supposed to have lived did a creditable witness appear? My understanding is it was many years, even many decades!

i think my feelings r private to me how i feel should show by how i live

I don't mention it around people I'm around briefly unless they are trying to "convert" me or something, at which point I just say, "I'm an atheist and I think all of that is completely ridiculous." For people that I am around regularly (coworkers, extended family etc.), I say pretty much the same thing.