When I think dive bar:
Fairly small; namesake of this board on the larger end.
No food or extremely limited menu (popcorn/bar nuts/chips & dip/pickled eggs/pizza slices)
Regulars are a must
Older construction / parts in disrepair
TV's are few and far between, not a main attraction
Dimmer lighting, but not in a club sort of way, is a plus
Cash bar only is a huge plus, but not a necessity