Comedy on the street comes from incongruity - the wrong person in the wrong place, the sign that means something different in context, the accidental rhyme between two strangers, the dog doing something undignified in a dignified setting.

You cannot manufacture it. You can only be in a frame of mind to notice it. Go out specifically looking for funny. It changes what you see.

Watch for: obvious jokes - a sign saying 'Fresh Fish' next to a suspicious-looking man has been done. Look for the subtle, the surreal, the things that make you snort quietly before you even raise the camera.