It seems to me that to start with, you can change the street itself. Just put a big grassy median to narrow the street, slowing down traffic and making walking easier. Then you start the process of bringing the shops closer to the street. If you were a dictator, you could just tear down everything. But in the real world, you'll have to settle for eliminating minimum parking and setback requirements for existing buildings, and requiring new structures to be closer to the street. How's that for a start?