The best way to determing who is approaching before seeing them is to rely on other senses. For example, if your uncle never showers then you might be able to smell him even if you can't see him coming. In some cases it may also be possible to tell who is approaching by relying on knowledge about their habits. For example, if someone is coming through the door at six o'clock, and your father usually comes by at that time, then that person is probably your father.
