When I was younger I always laughed if I tried to make eye contact no matter who the person was(I still do). Now I just look between that person's eyes or somewhere above the person's head to give them the feeling that I'm listening and so I won't laugh.
Depends on the situation. I mean are we talking? Or do they just walk up and stare at me? The first - i'd look them back in the eye and have a convo. The second - i'd call the police. Jokes, i'd turn away.
Ugh, I'm horrible with eye contact. I spend 90% of my conversations staring absolutely ANYWHERE but the person's face. It's just horribly unnerving looking into a person's eyes. The only time it doesn't bother me is when I'm all rage-ified and angreh.
Sounds totally like me until a few years ago. I partly got over it; I still look away automatically when crossing someone's glance, but now I'm easy with looking back at a friend, or when talking to people.
If it's a woman I have extreme difficulties keeping eye contact. (Unless it's family or a long time friend.) I don't know why. Anybody else, no problem. I look back, possibly ask if they need anything.