Marching isn’t as relevant to war as it used to be in the ancient era. However, marching well as a beginner soldier is probably key to getting promoted.
Doing well in a training game is far less important than doing well in the real game. However, a young soccer player will be lucky if he/she was picked for the real game having trained badly.
Whatever you decide to do, you will always have to do the equivalent of marching well. It doesn’t matter if you are an executive with the greatest reputation, a master analyst or a basketball player of repute. In a new role or environment, you’ll have to do the simple things right – get a deep understanding of the numbers, do the pre-work and train very well.
There’s a saying that a large part of success is showing up. It is more likely that by “showing up,” they meant showing up with a great attitude no matter the situation or task. A big part of being professional is being prepared to do the small things right. These may not be the most enjoyable parts of the job and probably were not the reasons you decided to do the work.
The greatest generals may not have enjoyed marching. But, they marched well all the same. Excellence, as Aristotle said, is not an act, but a habit.