There's a lot of situational and environmental clues in APB that can help put you in the right direction if you pay attention. Everything you mentioned plus stuff like noticing when pedestrians start running, watching for boxes and crap that people kick around corners while peeking, listening for the environmental sounds (dogs barking in some areas for instance) that are on a trigger, the radar, and a myriad of other stuff I can't think of right now. Oh, and luck.