By working a healthy 8 hours a day, and integrating walking into their everyday activities: walk to the store instead of taking the car or getting things delivered, for example. Although I do agree that it depends on the environment you live in - whenever I found myself in dense built-up inner-city neighborhoods with a lack of green, my step average was just half of what it was in more walkable, leafier neighborhoods. While not having lived there myself, I imaging US suburbs would be equally detrimental to my walking habits.