Are you aware?
Are you aware of the view around you? From your desk at work? In your seat on the train or bus? How about at your table where you eat lunch each day? Are you aware of the view? Of what's happening around you? Of who is coming and going?
Now I am not saying you have to be paranoid - just present.
TIP: Notice things. Position yourself where you can see things in front of you. Don't sit at a table with your back to the door. Know your entrances and exits. Park your car near a street light and not in the shadows. Try to understand your environment and what compromises it may or may not have.