Your first defense is AVOIDANCE and the second is ESCAPE. Anywhere you are, look and plan for these factors. Most people doing a personal attack, where you are touched, are skilled in fear and violence... on Y O U. The attack will be thought out while your guard is down. Remember you have only three steps before the attacker's physical response kicks in, and that is if he is standing still. You are very unlikely to get a gun and even a longish knife may be illegal to carry. Buy a souvenir sword, smile, that is legal or a cane. But chances are any weapon you have will simply be taken from you and used on you.
Using trusted tour guides that you get via your hotel can help. Do not get drunk. If meeting a policeman with a gun, put your hands up regardless of what is discussed. Sit to appear less threatening. Remember a police uniform does not always contain a real policeman, and note that many foreign cops wear civilian clothing. Same for military. Try to have someone videoing any trouble. If you get in a fight, get the attacker's skin under your fingernails to have some of his DNA.
Theft is only the beginning because kidnap is the largest worry in terms of personal safety. You can be taken from anywhere, hotel, pool, you name it, and if u r in a country where those things just happen, likely near-by people will ignore you, and your guide will run. If taken, work hard to make yourself human to them, kids photos/talk about etc., and get to know them as people, too.
Register with the local U S Embassy on arrival where you can also get up to date local info of dangers. Travel in groups and in public places not frequented by Americans. Dress like a local and keep your voice down and your eyes moving.
This is written by Charles @ yahooanswers.com