Hi MKnight Welcome Well if you are asking about how we do categorize articles technically than i have to refer you to How do I add an article to a category If it was not the case than the way i proceed is the following I read the into of the article and find that it is about an Armoured fighting vehicle I go to that article and check in which category it is contained The answer found is Category Armored fighting vehicles But in this category there are other more specified sub categories such as Category Armored fighting vehicles by era and Category Armored fighting vehicles by nationality I then choose Category Interwar armored fighting vehicles and Category Interwar armored fighting vehicles as the more appropriate categories for the article Wiki me up