"All wars should be governed by certain principles, for every war should have a definite object, and be conducted according to the rules of art. War should only be undertaken with forces proportioned to the obstacles to be overcome."
Or perhaps in modern language, "Know what you want to do, know what will be the consequences of doing it, know what you are up against and know what you will need to get the job done". The principle of "beginning with the end in mind" and "employing economy of force" seems a simple and straight forward guide to conduct, but the clue is in the word "guide" in that that is what you have. There cannot be strict rules and directions when it comes to application of this principle because much of the "knowing what to do" comes down to judgement and an element of educated guess work.
However failure to apply even a modicum of forethought to this principle of military behaviour litter history with examples of often disastrous or near misses of wars and campaigns that seem obviously ruinous to the all seeing "hindsight" but in many cases included a good helping of poor judgement and wishful thinking.
In general, Napoleon was probably one of the best practitioners of his own maxim and certainly in the early years was very precise and clear about his objectives and what he needed to do to bring them about; which usually included the grand battle of decision engineered with his careful preparation that made sure that he had most of the advantages on the day of battle. The campaigns of 1805, 1806 and 1807 shine out as the master at his best. However even the great man had is "off days" and the Egyptian Adventure, The Peninsular War, which he allowed to persist even when the facts pointed to adopting another policy and the invasion of Russia in 1812 are classical illustrations, with all the benefit of that all seeing hindsight, of not applying a thorough application of knowing what you want and how you are going to get it.
Even today modern military minds and governments struggle with this guiding principle and the war in Syria and the wider conflicts across the Middle East illustrate perfectly how complicated these situations can very quickly become.
For the wargamer, these ideas of force economy and objective setting mainly get tested on the tactical tabletop and less often on the campaign strategic level, that crops up more often in our board games.
The ability to assess a tabletop situation and decide what can be achieved with the resources at hand is what makes, for me, our hobby one of the most interesting of pastimes. If you then throw in the added fun of getting to know the personality and playing styles of your friends the fun gets multiplied. One of the best aspects I have discovered over time from playing C&G is that the rules allow the players to explore that often overlooked aspect in our wargames, that of keeping a reserve to either keep you from losing or for applying the Coup de Grace. The fatigue modelling in C&G that I have not seen done as well or at all in other rule sets means that the player who is able to apply the rules of force economy as discussed in this maxim can get the chance of recreating the "final blow attacks" that are the classic reward for the commander who is able to picture the end game.
The War of Method is a principle we can strive to apply at all levels of wargaming and whether we are studying a campaign map and assessing our intelligence reports or looking across a tabletop vista and deciding where to launch our main attack, beginning with the end in mind should be our start point before working out what we need to do to achieve that ending.