The other answers here are good, but I just want to add a few points.
If your character is street-smart, they need to know how to get money quickly. In your case, your character would have needed money while on the streets. Naturally, they should display their knowledge regarding this. For example, they should be able to distinguish between rich and poor people. They might say phrases like 'Follow the money', if they're on the run with others and are looking to mug someone. They might know which areas are richer and which are poorer so that they know where to target.
Your character would also need to know how to find shelter (especially when needed). They might know that committing a crime in front of the police can lead to a night in the cells (which are safe from the gangsters outside combing the city for you). Your character might have some old connections who would be willing to help them out and provide shelter. Your character might know that the sewers are quite safe to rest in at night as virtually nobody goes there.
Your character would need to know how to stay hidden. They might know that sometimes the most outlandish outfits are the ones that get ignored by their pursuers as their pursuers are expecting them to be hiding and not attracting attention. Your character might know that if they cover themselves in blood then they won't be noticed by the people who just started a massive shootout to kill you. Your character might know that if they pretend to be part of a family then they won't get spotted by the people who are looking for a single orphaned teenager.
Your character would need to know how to follow someone (and avoid being followed). Your character might know that an easy way to follow someone is to stain them with something like blood or paint so that the liquid leaves a trail on the ground which can be followed. Your character might know that the best way to avoid being followed whilst walking is to turn the corner, camoflage themself and then come back around the corner to walk in the opposite direction, so that the follower is left looking in the wrong direction. Your character might know that the best way to avoid being followed in a crowd is to simply crouch-walk, so that their follower simply can't see them.
Your character also needs to know how to get food. Your character might know that there's a free volunteer-run food bank two streets away who give free food. Your character might know that rich people are more likely to throw unopened food away, meaning that they can find food in bins of rich estates. Your character might know that his £1.50 might buy just a burger at the local McDonalds, but it could also buy a 2-litre bottle of lemonade and a 24-pack of Walkers in Tescos.
Overall, your character should know that little extra information that gives them the edge on the streets in whatever they're doing.