It is increasingly common in large urban areas for neighbors to interact less. In my opinion, this results in a declining sense of community and the solutions must be individually motivated.
In most cities today, the lack of connection between neighbors has caused less culturally unique neighborhoods. An illustrative counter-example to this would be famous neighborhoods such as Venice Beach in Los Angeles and Greenwich Village in New York City. In the past, individuals living in these areas shared similar values and that led to a flourishing of a unique culture. One result of such a sense of community was the “Beat Poets” of Greenwich. Related to this is the fading distinctiveness of communities that have value for locals and tourists alike. An individual living in a district in a major metropolis today feels little sentiment for its streets, buildings and other inhabitants and therefore derives nearly nothing in the way of a singular shared identity.
Remedies for the problems detailed above involve individual initiative. Governments attempting to contrive a sense of community will likely only provoke backlash. Instead, individuals could choose to live in parts of a city with a heritage that suits them and not join mass movements toward gentrification. A standout example of this would be expatriate enclaves in developing nations. These communities are able to preserve some of their cultural traditions and are entirely the result of individuals choosing to live together with those who represent their values and interests. This could be replicated on a larger scale if city residents choose their homes more thoughtfully and are more respectful of the traditions of any given community.