What you need to do is look at almost any video of a general wild reef landscape except of course, those targeting a specific group or shoal (PBT for example) and look at the species most prevalent in the video. There will generally be clouds of small fish (anthias, cardinals, damsel, etc.) very few larger 'spot' fish- they may swim through the shot but they generally don't hang around. IMO if you want a 'natural' looking reef you need to mimic that especially in a large tank, keep the large fish to a minimum and load it with small species (but do your homework first!) and watch the reef come alive.
This video show what I mean