Before I get into this, a note to all Sherlockians: Go check out Andrew Lane's Young Sherlock Holmes book series if you haven't already! Thank you.

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I once compiled an essential list pertaining to systematic workings of Sherlock Holmes in personal journal, and encouraged me to share it here; so here we are. 

Let's face it: I'm not a criminal investigator. Far from it! However, especially because I'm more of an artist, writer, literature lover and conceptionist, the philosophy of logic appeals to me as much as the philosophy of... well, everything! Compared to hard sciences or cold reasoning and analysis, an artist (much like Da Vinci himself) is not restricted by the means and tools at hand, and as such my own philosophy is a complex web of insights taken from the greatest minds and cultures of the world. The following commandments pertain to Sherlock Holmes -- a character imagined by the ingenious writer, physician and logician, Sir Arthur Conan Doyle (Sherlockians! Y U NO LIKE PROF CHALLENGER?) -- and have been compiled by me, from the books, of certain axioms and theories to consider in contemplation and practice. These commandments also increase efficiency of rational thought process, however based on your trades, you are free to disregard some of them. 

1. From what you see, observe. From what you observe, deduce.The little things are infinitely the most important, and everything in this world is relative.
2. When you have eliminated the impossible, whatever remains, however improbable, must be the truth. Balancing probabilities and choosing the most likely is the scientific use of the imagination.
3. It is a capital mistake to theorize before one has data.Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. It biases the judgment. Never guess, as it is a shocking habit — destructive to the logical faculty.
4. Consider that a man's brain originally is like a little empty attic, and you have to stock it with such furniture as you choose. A fool takes in all the lumber of every sort that he comes across, so that the knowledge which might be useful to him gets crowded out, or at best is jumbled up with a lot of other things, so that he has a difficulty in laying his hands upon it. A man should keep his little brain attic stocked with all the furniture that he is likely to use, and the rest he can put away in the lumber-room of his library, where he can get it if he wants it.
5. 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. Otherwise your energy and attention must be dissipated instead of being concentrated.
   
6. When a fact appears to be opposed to a long train of deductions, it invariably proves to be capable of bearing some other interpretation.
7. What you do in this world is a matter of no consequence. The question is, what can you make people believe that you have done? 
8. In solving a problem, the grand thing is to be able to reason backward. There are fifty who can reason synthetically for one who can reason analytically.
9. (When in abstract analysis) It is of the first importance not to allow your judgment to be biased by personal qualities. A client is a mere unit, a factor in a problem. The emotional qualities are antagonistic to clear reasoning.
10. Never make exceptions. An exception disproves the rule.
11. (Reinterpreted from William Winwood Reade) "As a single atom man is an enigma: as a whole he is a mathematical problem."  While the individual man is an insoluble puzzle, in the aggregate he becomes a mathematical certainty. You can, for example, never foretell what any one man will do, but you can say with precision what an average number will be up to. Individuals vary, but percentages remain constant. So says the statistician.
12. Life is infinitely stranger than anything which the mind of man could invent. We would not dare to conceive the things which are really mere commonplaces of existence. If we could fly out of that window hand in hand, hover over this great city, gently remove the roofs, and peep in at the queer things which are going on, the strange coincidences, the plannings, the cross-purposes, the wonderful chains of events, working through generations, and leading to the most outre results, it would make all fiction with its conventionalities and foreseen conclusions most stale and unprofitable. There is nothing so unnatural as the commonplace.
13. Singularity is almost invariably a clue. The more featureless and commonplace a crime is, the more difficult it is to bring it home.
14. Circumstantial evidence is a very tricky thing. It may seem to point very straight to one thing, but if you shift your own point of view a little, you may find it pointing in an equally uncompromising manner to something entirely different.
15. There is nothing more deceptive than an obvious fact.
16. Look for consistency. Where there is a want of it we must suspect deception.
17. As Cuvier could correctly describe a whole animal by the contemplation of a single bone, so the observer who has thoroughly understood one link in a series of incidents should be able to accurately state all the other ones, both before and after.
18. Violence does, in truth, recoil upon the violent, and the schemer falls into the pit which he digs for another.
19. Any truth is better than indefinite doubt.
20. One should always look for a possible alternative, and provide against it.
21. What one man can invent another can discover.
22. When water is near and a weight is missing, it is not a very far-fetched supposition that something has been sunk in the water.
23. I am not the law, but I represent justice so far as my feeble powers go.
24. Education never ends. It is a series of lessons with the greatest for the last.

Now let us revise the commandments succinctly:

1. Observe and deduce every little data.
2. Everything in this world is relative.
3. When you have eliminated the impossible, whatever remains, however improbable, must be the truth. 
4. Never theorize before one has data.
5. Recognize which info is incidental and which vital, otherwise dissipate your focus instead of concentrating. 
   
6. A man's brain is like a little empty attic, so stock it with your chosen furniture.
7. When a fact appears to be opposed to a long train of deductions, it invariably proves to be capable of bearing some other interpretation.
8. The means are often more important than the results. 
9. What can you make people believe that you have done in this world? 
10. In solving a problem, the grand thing is to be able to reason backward.
11. (When in abstract analysis) The emotional qualities are antagonistic to clear reasoning.
12. Never make exceptions.
13. As a single atom man is an enigma: as a whole he is a mathematical problem.
14. Life is infinitely stranger than anything which the mind of man could invent. There is nothing so unnatural as the commonplace.
15. Singularity is almost invariably a clue.
16. Never rely solely on circumstantial evidence, and never fail to look from different points of view.
17. There is nothing more deceptive than an obvious fact.
18. Look for consistency. Where there is a want of it we must suspect deception.
19. Thoroughly understanding one piece of the puzzle will give you insights on the links with the rest. 
20. Violence begets a backlash.
21. Any truth is better than indefinite doubt.
22. Always look for a possible alternative, and provide against it.
23. What one man can invent another can discover.
24. Investigate vacancies, odds and discrepancies, because a missing clue is nearly as valuable as additional one. 
25. Though insignificant, you represent justice.
26. Never stop learning, because the fruit of labor is nigh. 

Of course, the Philosophy of Science and Logic are far greater subjects than what can be inferenced from Sherlock Holmes (who uses more of systematic deductive means than anything else), but those are something I'll muse with myself (or with anyone interested) later when I have sufficient time. Albeit, I do admit the concise habits and traits of Holmes mark for effective reasoning, and often I blend them with either my own ideas and disposition or those of other great thinkers.