Many of the replies so far are more 'general life advise' answers. To me 'street smarts' is what the rich people that I know are - none of them have degrees, but they're all wealthier than the educated people like doctors, lawyers, engineers etc. around here. These are all people who run retail or wholesale businesses, small chains of Walmart-style shops, building materials, run contracting/real estate development companies, even fast food joints - that sort of thing. These people can't tell Australia from Africa if you give them a map, and none of them have ever heard about a sine or integral or Pointcare's conjecture, yet they drive Maseratis and have dozens of properties. Why did these guys succeed and others businesses fail or barely make enough to live off? That is what street smarts is to me, what these entrepreneurs have that made their businesses a success, and what others lacked.

Anyway in trying to identify the nature of this street smarts, I have analyzed some of these people that I know, asking them questions that are still appropriate (i.e., not straight-out asking them about money) and don't make me look like a weirdo as much as I could, and keeping in mind a certain sort of anti-intellectualism that many of them exhibit (and that, in some cases, has paid off very well for them). I recognize that my thought processes are so far away from theirs that it's very easy to fall back into cargo-cult imitation, but still, I think that a large part of their success is in their deal-making capabilities. This breaks apart in two phases: phase one is connecting to the right people, phase two is making the actual, concrete deal.

Phase 1 is facilitated by having a large network, just knowing many people, and this is done by being a person that people want to be around with - be a nice guy, but not a pushover, be confident, dominant without being an asshole, and be in general nice to be around. This is a hard challenge to me, it isn't easy to get to know as many people as possible, letting them know what you do and finding out what they do, and making that all happen naturally. E.g. it's easy to 'meet' random people by chatting them up in the supermarket - but how will you tell them what business you're in? Smalltalk about the weather will only get you so far, how do you (efficiently, i.e. without turning them into full-blown friends with the associated time investment) get them to the point where they remember you as the go-to guy in your line of business, or get them to the point where you can call them when you need something, so that you always have an 'acquaintance' for whatever you need, who you can call?

Then there is phase 2, which can basically be summed up by "at any point in any any negotiation, you need to remain willing to drop everything and just walk away". This means being very aware of cognitive biases such as loss aversion etc. You have to be tough as nails here - be on friendly terms with people, so that they want to help you out, yet not exploit them because that will blow your relationship with them. You have to get people to a point where they are happy if they can do you a favor.

This is already getting too long, but let me share with you one (in my opinion) example of 'street smarts' that the Belgian and German readers will recognize: the soccer keeper (goalie) Jean-Marie Pfaff. He used to be the keeper for the Belgian national team, he also played for Bayern Munchen in the 90's I think. Anyway he has a reality TV show now, his daughters are models and kinda famous so they all ride the tails of his fame now, kinda like Hulk Hogan.

Anyway like I said, he has this reality TV show. In one episode, and this really struck me, there was a guy who was living in the same village as Jean-Maria and he came to the door of his villa, rang the bell and dropped off a bag of potatoes. Not ordered or anything, he had just harvested, has potatoes, and thought to drop off this bag. He was so eager to please this rich/famous guy that he'd out of nowhere brought him a 3 euro bag of potatoes. That, to me, means that this Pfaff guy has street smarts - he manages to be so likable that people that they do thing they'd not do for others.