Knowing how much time I spent getting through plot in a number of the books I read, I would have started with some locked room mysteries and the Sherlock Holmes stories, which provide less plot and helps build clue identification and deciphering skills and techniques.  This would have helped me when reading the longer mystery novels in identifying what was truly important to the mystery as compared to the red herrings and macGuffins.  I will also be more selective with the movies I watch to make sure they are true mysteries and not simply suspense thrillers.