Greg Ellifritz is a Brazilian Jiu Jitsu black belt, defensive tactics instructor and police officer from central Ohio. His experience also extends to quite a bit of overseas travel in environments that prohibit firearms ownership and carry.
In this article, Greg talks about what criminal actors often do prior to the attack. Scratching, looking behind themselves, and grooming themselves are very common pre-assault indicators. In addition to these, Greg talks about how hand positioning above the waistline and clenched is an indicator that the person is ready for action. Their physical movements, such a walking parallel to you, keeping pace, or vectoring on a collision course are also important to watch.
Ellifritz also addresses things we can do to make ourselves a harder target. Walking upright, with friends, and display confidence. He cites a list of actions that make you look like a victim as well, and adds in a facial drill you can do to show that you will not be victimized. He says that if you can turn your expression from the surprised face to an angry face, you have a better chance of being passed up for an attack. The idea is that you would offer active resistance to the criminal and that you are not worth the effort.
This is a very good article, as it condenses a few things from resources such as Paul Eckman and the authors of Left of Bang. This quick breakdown is easily digestible even by people that have no interest in carrying tools for self defense (though you may want to edit the introduction story). Finally, it shows that you don't have to be a victim even in places where you cannot be armed. If you are interested in more tips and tales from Gregs trips abroad, look for his book, Choose Adventure: Safe Travel in Dangerous Places.
The full article can be found Active Response Training, HERE.