ELIMINATE THE IMPOSSIBLE.
The Excessively Complex, too, particularly if you wish to solve mysteries. First read The Sherlock Holmes Handbook: The Methods and Mysteries of the World's Greatest Detective. It's Book Review No. 14. The contents will be left to the reader as an exercise. I did like one of the Holmes quotes from the end of the work. From "The Adventure of the Copper Beeches" comes a theme for a model railroad display now a-building. "The lowest and vilest alleys in London do not present a more dreadful record of sin than does the smiling and beautiful countryside." Why else would Holmes and Watson be coming and going from Paddington Station or Victoria Station.
(Cross-posted to Cold Spring Shops.)