Though it varies from state to state—and I'm not a lawyer—it's my understanding the law essentially says a citizen has the right to use deadly force if he feels that his life is in immediate danger. In other words, there is no legal obligation to retreat, or attempt to retreat, from a deadly attack.
Opponents of this law are acting like this is a new and amazing part of the self-defense legislation. In fact, it has been the law of the land in many states for quite some time. This is how it works. In the aftermath of a deadly encounter the citizen tells investigators he was afraid that he was about to be killed, or sustain serious bodily injury. If the police and prosecutors find there's enough evidence to the contrary, the citizen is charged with a crime. At his trial, the citizen, through his attorney, raises the issue of self-defense and it is up to a jury to decide if it was reasonable for the citizen to be in fear for his life and if his actions were a reasonable response to the threat. Clearly, the Stand Your Ground law is not an automatic "get-out-of-jail-free" card as some would have you believe.
However, as I have said before, private citizens should do everything in their power to get away when it looks like things are going to get bad. Your defensive firearm should be your exit ticket. By avoiding trouble, you don't lose face. What you do avoid is having to kiss gravel, get handcuffed, face a lengthy interrogation and investigation and, maybe, a very expensive courtroom experience.
Obviously, there are times when you simply can't retreat. The defense of your own home might be one example. Another might be if a family member was in immediate danger and about to be killed or seriously injured. Are you beginning to see why getting advice from a criminal defense lawyer at the same time you decide to carry a defensive handgun might be a good idea? The best accessories for your defensive handgun are professional training and common sense.