My neighborhood is old. Lots are generally 1/10 acre, and many houses are under 1000sqf. So questions for us aren't about building new, but rather about how to

My neighborhood is old. Lots are generally 1/10 acre, and many houses are under 1000sqf. So questions for us aren't about building new, but rather about how to maintain the neighborhood for the future. How do we replace old houses that are falling apart without changing the essential character of the neighborhood? How can we get some more small businesses and restaurants without giving way to strip malls and big boxes? And the current controversy... there's a possibility that a light rail route will pass within a block of my house, down the major in-out drag for the immediate neighborhood. The light rail does us no good, but because it's a relatively short residential pass, we will have a hard time resisting.