"Do bold experiments that are cheap to try out."The transportation commissioner of New York City, Janette Sadik-Khan, gave this great talk at TED explaining some of the things that she and her team did to make NYC's streets more people-friendly.
What's so impressive about most of the examples that she gives is that they are things that are cheap and quick to do. This isn't about investing billions of dollars in expensive infrastructure. It's about making choices, and then buying a few cans of paint or whatever. All cities can do a lot of these things!