Study one of the “parent” design disciplines of urban design at a good school – architecture, landscape architecture and/or urban planning. The latter is best in combination with one or both of the former two. The biggest lesson you will learn in school will be from your classmates and peers, not the instructors.
Drawing is the essence of urban design communication
Learn to draw and hone this key skill every day. There is no more fundamental skill to a career in urban design. Keep a sketchbook with you at all times. Learn by drawing the world around you; while doing so, try to understand how people use – or don’t use – urban spaces and places and buildings. Measure and document those places, using your own body and stride. Drawing is not a tool or technique like computer modelling is. It is the essence of urban design communication.
Almost as important, learn to express yourself and your ideas, as well as those of others, both in words and illustrations.
Never stop learning
Read and continue to re-read the core literature, but never stop learning through observation and lifelong study. I would start with the work of both Jacobses (Jane and Allan), Kevin Lynch, Gordon Cullen, Palladio, Colin Rowe, Christopher Alexander, Camillo Sitte, William H. White and Monty Python. (Yes, a sense of humour does help, in almost all things.) Try to understand the influence that time, place and cultural context have in the formation of their lasting contributions.
Learn what “human scale” means. It is not an abstract concept, but nonetheless as elusive as the Higgs boson particle!
Don’t let the search for the great get in the way of the good. A lot more everyday goodness is what we need in our urban environments. There's so much repair needed.
Identify key mentors and heroes, living and past, and be willing to learn from them, in large and small ways.
Be a team player
Play well with others. Work with fellow design professionals and laypeople in a team context, but also know the value of your own ideas. Having said that, be willing to let go of ownership of your own ideas; they only have value in urban design if enough other people embrace them and want to see them become reality. This definitely includes politicians and decision makers.
Ideas are cheap, implementation is paramount. There is no greater truth than this, despite what professors may say, including me.
Become a mentor yourself. Pay it forward.