Motion often signifies life, motion often signifies change and motion is easy to capture on film or digital media. Apart from the usual technique of panning, with a little bit of practice, you could do a combination of panning and fixed focus blurring.
This one was shot in a subway station, with minor panning and partial fixed focus. The fact that it was done pressing the shutter while coming down the elevator in available light, made it partially blurred. It was shot on D200 in color and later desaturated.