There are so many books out there about how to practice deductive reasoning like Sherlock Holmes, many of which have certain cornerstones of thought.
The ones I'm thinking of are constant mindfulness and practice- two things which often allude Watson, as well as ourselves. At my workplace, it's usually my job to deliver the evening batch of IV room products from the pharmacy upstairs to all of the patient floors. But that day, the refrigerate-only items were gone, and the room-temperature products were left. I questioned everyone around me, but nobody knew what had happened to them. So I simply took the room temperature products and left.
It ended up that I had wasted an hour of time, because the worker from the overlapping shift had delivered the necessary items and I simply took up what the night shift was supposed to deliver. The worker was furious and yelled at me for wasting time. Indeed, I should have checked the times and dates on the products to ensure that the times that they were due were those signifying those products were mine to deliver. The lack of refrigerate-only items should have given me a clue as to what had happened.
But I had no reason to suspect that anything was amiss. No notes, and none of the pharmacists or other technicians knew what had happened. Retrospectively looking at the situation, I could have deduced that someone had done me a favor and done my duty for me. My mindfulness was obviously not there, and despite trying to practice being Sherlock Holmes, one can't be Sherlock Holmes until one is constantly mindful and in practice of logic reasoning.
I shouldn't be so hard on myself. After all, Sherlock Holmes didn't just wake up one day and become the great detective that we know him to be, so I just can't have the powers of deduction by wanting it one day.
So I end with this. "It is of the highest importance in the art of detection to be able to recognize, out of a number of facts, which are incidental and which vital." REIG

