Start with the people you work with, or those in your church or Bible study group. Try looking for clues as to who's really happy or who may be struggling, burdened or feeling down. And then, next time you're in a conversation with one of those people, make a point to find out more about the person, just allowing and encouraging him to talk about himself a bit. Make notes of your observations. See how the list grows.
Vision takes practice.
But it is step one in being a Good Samaritan. We can't help if we don't see. That traveler at O'Hare caught his plane because a man was observant enough to notice a plane ticket lying on an empty table. But in Jesus' story, the priest and Levite had vision, too, yet nothing happened. Vision alone isn't enough.