I always scope out the parking lot as well. Hard to tell whether a vehicle is leased or not but if there's clearly a large number of older vehicles, especially inexpensive models I judge it to mean that there is a disconnect between how management is valued and the rank and file is valued. One place I worked also had a separate lot for management. The lot for the rest was five minutes away, unpaved and filled with cheap cars. Bad sign.

Trying to determine the ratio of women to men in the office is a pretty good indicator too. An office with an even balance (especially in each work group) I believe will work better than groups that are overwhelmingly male or female. I think that just having members of the opposite sex nearby keeps people on their best behaviour. I have seen it work and the lack of it fail to work.

I'm curious about the fish tank though. Never heard that one so I'll keep an eye out.