Liveable & Sustainable Cities A Framework

In the space of just four decades, Singapore made the leap from an urban slum to a thriving global city-state. Today, it is a densely populated metropolis, with more than 5 million people inhabiting 710 km2 of land. In most liveable city surveys, it is rated one of the few high-density cities that are able to achieve high liveability standards.
How did Singapore achieve this transformation and balance of density and liveability? What did it learn in the process?