Please read this article: How to Design our Neighborhoods for Happiness.
This article talks about developing relationships with the people around us, but it’s also very pertinent for sustainable living. It talks about community spaces for increasing interactions with your neighbors – which can also be used for community gardens, community composting, etc, which can also increase the self-sufficiency of the people living there.
Another thing mentioned in this article is smaller streets, and ensuring sidewalk space. I would add bicycle lanes. If my time in the Netherlands has taught me anything, it’s that bicycling can be a very fun and safe alternative to fossil-fuel-consuming cars, but it’s not reasonable to ask people to ride their bicycles everywhere with the current infrastructure and attitudes in the US. It’s just not safe enough. Designing or re-designing neighborhoods to be safe and inclusive for bicycles will help make communities happier, healthier and more sustainable.
The last point in the article is possibly the most important. Having a sense of community increases your ability to organize effectively to implement change. This is badly needed.
Also check out the Piscataquis Village Project in my awesome home state: Maine. It’s a clear and unique vision for a car-free village that focuses on community.