On Monday, we talked about using a dictionary or thesaurus when you're in need of different ways to say or describe something.
Sometimes you may feel that what you need can't be found in a book. So you take a class, say, in police procedure. Or you talk to a friend or acquaintance in the police department.
Before you do that, though, do some research. The police or contact person with the police can't give you the answer you want unless you know what you want. You're going to have to narrow down your question. Rather than asking how police investigate a crime scene, try to narrow it down to specifically what you need to know.
To narrow down your question, you can turn to books. For example, I have a textbook called "Practical Homicide Investigation: Tactics, Procedures and Forensic Techniques." It's the second edition and it's pretty old (1993), but I still check it first for the basics.
There's a guy online who would be a good source: Lee Lofland. He has a Writers Digest book called: "Police Procedure & Investigation". You can also check out his blog, The Graveyard Shift .
For most subjects, it's fairly easy to do research. And sometimes you can ask experts, either in person on online.