Many plaintiff's lawyers limit themselves to reading only legal articles written by lawyers who also represent plaintiffs.
There are lots of good resources out there written by members of the defense bar. This article, by Richards H. Ford, is a fine example. Titled "Negligent Security: When is Crime Your Problem," Ford provides an overview of the circumstances under which negligent security cases can arise and the applicable law. To be sure, the law of each state is a little different. But, if you are thinking about accepting representation in on of these cases, you will get off to a good start by reading this article. At an absolute minimum you will get a solid handle on how your opponent will undertake to defend the case.