When you’re walking to wherever it is you go again, spend some time looking up at the buildings around you. Take notice to patterns and details, windows and escape routes. Make sure no one is trying to escape while you’re doing it, they’re likely to land on your face.
If you’re lucky enough to have access to your roof, take a moment to go up there at midnight and observe the environment around you. For an extra special treat, wait to do this during a full moon and bring some music with you. Two things to note: if you fall, it’s not my fault. If someone thinks you’re a robber, jump.
During broad daylight or in the evening hours, search for shadows in unexpected places. this is especially fun during a cold and foggy san francisco night. Because cold and foggy san francisco nights usually suck.