Today I have to take my cat to the vet, long-distance, so this will be a brief entry.
I'm thinking about eye gaze.
With all the child-rearing that I'm currently involved in, I meet a lot of different kids, and one thing I notice is the way that parents teach their children where to look. This happens both explicitly, as when parents insist that their children look them in the eye in a punishment situation, and inexplictly, through demonstration and observation.
I urge you never to underestimate a child's natural powers of observation. I think they must be adaptively selected for keenness when it comes to cues about emotion in adults; once the brain develops enough to grasp social cues of this nature, around age 9 months, watch out!
Adults are pretty good at this, too. Think about how much of the time you look around to see what someone is looking at - and then think about how certain you are of your judgment. It's amazing what a human being can deduce from of the tiniest motion of a pair of eyes. Is he looking at me? Is he meeting my eyes? Why does he keep looking at the door? Is he preoccupied with that stone in his hand?
Culturally speaking, different groups associate different meanings with the placement of eye gaze. I find that typically in American conversation, the listener is expected to maintain eye gaze on the speaker's face, while the speaker makes direct eye contact regularly but not continuously so as not to appear too forceful. In Japan, direct eye gaze can be considered an affront. My friend Sheryl yesterday was remarking that an Asian friend of hers accompanied her to dinner with a pair of her friends who were married, and did not make eye contact with the married woman through most of the meal - something that this woman noticed and felt odd about at the time, but which was later explained as a distinct cultural gesture of politeness. In a way it makes perfect sense: why would you ogle someone else's wife? Of course, this depends on how ogling is defined in your culture...
As you move into your created worlds, it's worth giving thought to how people watch one another in different contexts. Watching for social signals is very important - but clearly people can have very strict rules about what, and when, to watch. It can also be used very well as a physical decription to break up dialogue, and description of what a person is looking at at any given time can play an important role in point of view.