Some folk have a habit of just getting into the cab and then launching into a conversation, about the weather or whatever without telling me where they are going. Now a lot I do remember but a lot I don't, and so whilst they are talking I take a quick look at them for a clue.
Black ties and mournful expressions and I will start to head for the crematorium, flowers and smiles and it's good chance it's a wedding.
If it's morning chances are they are going to work and so I look for logos or works badges, easy if they work for Asda(Walmart) they wear the brightest shade of lime green you can get,( and believe me they would not wear these duds for anything except work).
Others have just the firms logo on a tie or a certain colour shirt or overall these are harder but I usually get them right. But my secret weapon is that I have a good sense of smell and can sometimes go on this alone. The most obvious one is our local scented candle factory, easy! the next is the fast food joints, they all have their own distinctive smell. We have two Italian restaurant' s on one street and I can smell who works in each by which uses the most garlic.
Within minutes of picking a fare up I can smell if they smoke (yes even wacky baccy) and if they have a dog, cat or other pet. Last week I picked a lady up and was able to tell her she had a horse and that she had recently used Neatsfoot oil on it's hooves. "Thanks she said what you mean is that I stink and need a shower then"