During rush hour the traffic can be really slow moving, when you are stopped or at a red lights, the thief will try to open your side door or break the window to grab your bag purse or laptop. The best thing to do is keep your door locked and valuable items out of sight.
Pick pocketing is a problem like in most large tourist cities, these thieves are professionals and you wont notice until your wallet or purse has gone. The best option is to try to not make yourself a target, keep bags closed and wallets or purses in inside pockets.
The gold ring scam, someone will seemingly pick up a gold ring and come over to you, they make out that you have dropped it. The con artist will then try to give it to you, when you reply its not yours they will say to keep it, in return for for the ring you can then give them money. The ring is worthless, the best way out is to either walk away or suggest to contact the police about the lost ring.