I give everyone respect and treat them with civility. You have to give respect to get it, so I give it first. I don't walk around with a chip on my shoulder thinking that people have to earn it. Someone has to give it first, and I'm willing!
This is the one major rule I have that helps me in working at the jail. If a person is of sound mind, they will usually respond in kind. When I walk around in an area filled with alleged murderers, I am wary but not fearful because I refer to them as ladies and gentlemen, and always use please and thank you when I ask them to do something. The only threats I've received have come from mentally unstable people. And I've had a "dangerous" inmate with law enforcement predjudices come to my aid when I was being attacked. I believe it's because I treated this inmate respectfully.
Basing your actions on predjudices is a mistake. You can't lump everyone together by color, sex, nationality, etc. We have members of the clergy in custody right alongside everyone else. Humans come in varying degrees of good and bad. Outward appearances don't guarantee what kind of person you are.
So, in interacting with strangers, I am polite and respectful to them. It doesn't matter what they look like or what the neighborhood is like. I've dealt with a wide range of people and everyone is basically the same. Sure, there are the psychotics that look just like you and me... so be ALERT during your interaction. But there isn't as much to fear as the media would have you believe.