Not so vital, but still worth mentioning, is placing weapon on a screen. Ways of doing it depend on the kind of weapon. For example:
all pistols in the same place, on the right and lower,
all shotguns more on the right and higher, and so on…
It is worth thinking over especially while planning the whole set. Unfortunately, restricted scope of possibilities to choose the angle and the height results in not many creators taking this opportunity.
Call of Duty World at War could be a good example. Weapons of the same kind have the same angle and place of embedding.