Sorry to hear about this. I've little advice that would be helpful in your particular case apart from what others have already said, particularly about not carrying too much and perhaps not carrying things that look as if they're expensive or easy to steal/sell on.

As far as being aware is concerned: I went to Teignmouth Folk Club not long ago and parked about 100m away down the street. (Teignmouth is hardly a hotbed of anarchy and crime.) As I left at about 23.00, I went to my car and put my guitar on the back seat, noticing two men walking down the street in my direction. I'd just got in the car and shut the door when I saw in the mirror that they were veering across the road towards my car. They didn't look particularly drunk or threatening but neither did they look as if they were lost or looking for directions. I hit the central locking mechanism just as one came up and tried to open the rear door. Our eyes met in the mirror where I'd been watching him and he just shrugged, then they both walked on their way. I still don't know what they wanted; to ask for a lift (why not come to he driver's window?), to try to take my guitar (?): whatever I'm glad I was aware of their presence and quick enough with the door lock. It's always worth being aware of what's going on round you.