"Public Places - Urban Spaces" — a recently updated textbook on urban design and planning — includes a review of six place-making frameworks by the likes of Kevin Lynch, Nan Ellin and the Congress for a New Urbanism. The frameworks range from criteria to manifestos, at scales from the region to the home. While each has a different orientation, in sum they offer a mix of touchstones, principles, characteristics, goals and approaches linked with "good" urban design. They're useful in developing standards for comparative evaluation, which can be applied adaptively toward creating healthy, democratic and attractive public space in cities.


Private rooftop garden in Manhattan. Source: Inhabitat

Matthew Carmona, Tim Heath, Taner Oc and Steve Tiesdell structured "Public Places - Urban Spaces" around dimensions (morphological, perceptual, social, visual, functional, temporal) and processes (development, control, communication) for consideration in adopting a "holistic" urban design process. They frequently refer to the integrated nature of these dimensions, as well as the importance of context and politics:
 
Effective place-making demands sensitivity to, and cognisance of, power dynamics in and across urban space and its production. Urban designers thus need to understand the contexts within which they operate and the processes by which places and developments come about. As in many spheres, there is often an implementation gap between theory and practice and, in the case of policy, between high-level, aspirational principles and local delivery (11).
Based on these considerations, along with initiatives by the Project for Public Spaces,Building for Life and the Urban Design Alliance, the authors outline a series ofquestions aimed at building "an agenda for improving the quality of place" (359). CitingErnest Sternberg, they discuss the threats to public space from "real estate markets that would treat land and buildings as 'discrete commodities'" (Sternberg 2000: 265), explaining that "without conscious concern for urban design as a process of restoring or giving qualities of coherence and continuity to individual, often inward-focused developments, overall place quality is inevitably neglected" (14).

The authors acknowledge the problems with assigning definitions and formulas to urban design, summarizing this point in the final chapter:
while most definitions of urban design are appropriate and valuable, they are also limiting and contestable. Although some useful frameworks from distinguished urban designers were presented, they were accompanied by the caveat that they should not be treated as inflexible dogma, nor reduced to mechanical formulas. Application of a formula negates the active process of design and downgrades the role of the designer and of design intelligence. No single set of rules (or objectives) can capture the scope and complexity of urban design, nor offer a step by step formula for successful place-making. It is an exploratory, intuitive and deductive process involving research into the problem posed and into the variable and specific conditions of time and place. The complex interactions between the variety of processes and elements in a place can, however, be examined and these can give generic clues to why some places succeed while others fail (359).
Thus, while it's helpful to set up common languages for evaluating and improving urban environments, the design process should, of course, be rooted in a thorough understanding of each project's unique and multi-faceted dimensions. This seems the best approach to collectively developing public space with the care that cherished private space receives.