The Rainbow Ruse, the Barnum Statement, the Fuzzy Fact, the Greener Grass technique, the Diverted Question, the Russian Doll, Sugar Lumps, Forking, and the Good Chance Guess.
These are all magic tricks described in the classic how-to manual of magician Ian Rowland, "The Full Facts Book of Cold Reading." When skillfully woven together, these tricks can convince even the most skeptical observer that you possess uncanny wisdom and insight.
For example, take the Rainbow Ruse. Here, one attributes to the listener both a personality trait and its opposite, as in: "I would say that on the whole you can be rather a quiet, self effacing type, but when the circumstances are right, you can be quite the life and soul of the party if the mood strikes you." Or, the Barnum Statement, an assertion so general that anyone would agree. And the Fuzzy Fact: a seemingly factual statement couched in ambiguity, as in: "I can see a connection with Europe, possibly Britain, or it could be the warmer, Mediterranean part?"
Writing in the Nov. 12 New Yorker magazine, Malcolm Gladwell presents a crash course in how such time-worn magic tricks have convinced the world of the scientific legitimacy and deductive powers of forensic profiling.

Gladwell cites the research on profiling, which shows they are accurate enough to lead to an arrest in only a tiny fraction of cases, less than 3% in one study by the British Home Office.
Partly, the failure of profiling may be due to the unscientific manner in which its premises were generated. For example, the well-known organized/disorganized typology of serial killers – which falls apart under empirical scrutiny – came out of a convenience sample of offenders interviewed using no scientific, standardized method. FBI profilers Douglas and Ressler just "sat down and chatted" with "whoever happened to be in the neighborhood." That's not how one generates good science.

Further resources:
The Forensic Psychologist's Casebook: Psychological Profiling and Criminal Investigation, edited by Laurence Alison
"The organized/disorganized typology of serial murder: Myth or model?" by Canter, D.V., Alison, L.J., Alison, E., & Wentink, N. (2004). Psychology, Public Policy, & Law, Vol. 10, pp. 293-320.
"Validities and Abilities in Criminal Profiling: A Critique of the Studies Conducted by Richard Kocsis and His Colleagues," by Bennell, C., Jones, N.J., & Taylor, P.J. (2006). International Journal of Offender Therapy & Comparative Criminology, Vol. 50, pp. 344-360.
Minds on Trial: Great Cases in Law and Psychology, edited by Charles Patrick Ewing and Joseph T. McCann (see especially Chapters 1 & 11, the latter a great account of profiling in the USS Iowa disaster)
"Criminal profiling: the reality behind the myth: Forensic psychologists are working with law enforcement officials to integrate psychological science into criminal profiling," by Lea Winerman, American Psychologist, August 2004.
Photos: Top: Robert Ressler (left) and John Douglas (right); Bottom: The presence of actor Shemar Moore in television's prime-time drama Criminal Minds hasn't hurt the popularity of criminal profiling.
ADDENDUM: Criminal profiler John Douglas, critiqued in Gladwell's essay, has issued a lengthy response that is printed in full at the Crimson Shadows blog.