Living in a city with subways offers an advantage to walking.
On your way somewhere or just out for a walk, you can use your environment to step up your walk. When I walk around my neighborhood, i incorporate the subway stairs in my walk. If i am approaching a light and it is changing or changed and a set of subway stairs are available, I do not stop and wait for the light. Instead, I run down the stairs and up on the other side of the street. This keeps me in motion and adds to my walk.