Here is a cool article on teaching field sense. Here's one really good quote:
Farrow has found that players who make poor decisions tend to glance at targets, rather than pausing on them. They're also more drawn to motion. "In a lot of team sports, you're attracted to the area of greatest movement," Farrow says. "But just be-cause there's a person running fast and waving his arms doesn't mean he's the best person to kick to."
And here is another interesting link, though interesting in a different sense.