When studying to be a judge, I was exposed to so many other forms of performance where precision plays a key role. If you want to judge performances in the Military Drill World, I suggest that you purchase my two World Drill Association books and then begin to watch not only military drill performances of all kinds, but other performances as well so that you will develop your eye for appreciating precision and various types of performances.
When watching performance after performance of military drill, your eye can then begin to miss things. Watching other precision sport performances can help avoid that. The videos below, and ones like them, will help you sharpen or create your observational skills.
Here is the playlist I have in development to educate judges, instructors and performers: