My answer to How do I cope with the fear of terrorism?
Answer by Ken Larson:
Study situational awareness.
“It is important to note that situational awareness — being aware of one's surroundings and identifying potential threats and dangerous situations — is more of a mindset than a hard skill. Because of this, situational awareness is not something that can be practiced only by highly trained government agents or specialized corporate security teams. Indeed, it can be exercised by anyone with the will and the discipline to do so. Situational awareness is not only important for recognizing terrorist threats, but it also serves to identify criminal behavior and other dangerous situations.
The primary element in establishing this mindset is first to recognize that threats exist. Ignorance or denial of a threat make a person's chances of quickly recognizing an emerging threat and avoiding it highly unlikely. Bad things do happen. Apathy, denial and complacency can be deadly.
A second important element of the proper mindset is understanding the need to take responsibility for one's own security. The resources of any government are finite and the authorities simply cannot be everywhere and cannot stop every potential terrorist attack or other criminal action. The same principle applies to private security at businesses or other institutions, like places of worship. Therefore, people need to look out for themselves and their neighbors.
Another important facet of this mindset is learning to trust your "gut" or intuition. Many times a person's subconscious can notice subtle signs of danger that the conscious mind has difficulty quantifying or articulating. I have interviewed many victims who experienced such feelings of danger prior to an incident but who chose to ignore them. Trusting your gut and avoiding a potentially dangerous situation may cause you a bit of inconvenience, but ignoring such feelings can lead to serious trouble.”