Sherlock sometimes uses a memory technique that he calls a "Mind Palace." This is not an invention of the screenwriters; rather, it is a method of aiding memory that dates back to ancient Rome. One of history's most famous real-life practitioners was the sixteenth-century Italian Jesuit missionary Matteo Ricci, who introduced the method to China.
As in the Sir Arthur Conan Doyle stories, the term "deduction" is misused. Like medical diagnosticians, hunters and yes, detectives, what Holmes actually uses a form of inference called "abductive reasoning," which is neither deductive nor inductive.
In this series, Watson was wounded in the shoulder but has psychosomatic/psychogenic pain in his leg. This is a sly reference to the original stories in which Arthur Conan Doyle was inconsistent about the location of Watson's war wound.
In the summer of 2011 Danny Boyle created a National Theatre production of 'Frankenstein' in which Benedict Cumberbatch and Jonny Lee Miller played the creator and monster and alternately changed nightly. Both actors then went on to play another Victorian creation Sherlock Holmes, both set in the present day, allbeit opposite side of the Atlantic.
Through the series, several Holmes stories by Arthur Conan Doyle are alluded to, either as episode names or in passing. For instance, "A Study in Scarlet" becomes "A Study in Pink", "The Greek Interpreter" becomes "The Geek Interpreter" etc.