Multilevel greenhouses, with artificial sunlight and machines that take water out of the air for irrigation as well as regular greenhouses for growing fresh food. Community gardens should be used as well to provide more fresh, healthy food for all communities. There should also be compost facilities nearby.
Machines that take water out of the air should also be used to supply drinking water.
Solar panels should be attached to the top of every building, fields of solar panels should be used to augment these small clusters of panels.
Magne rail trains used for long range transportation, electric trains and self driving publicly available cars for shorter distances.
Community housing complexes should be available for those who want it. In these housing complexes, multiple families and individuals would live together and form a small community/support network. People would work together to cook, clean and look after the members of the complex. Denmark has a similar system, you can learn more about these in the documentary "Happy".
Wireless access available for all, subsidized for those who cannot afford it. This will be one component of education outside the classroom. the tech community, hackers and others could work collectively to make the data on this network(s) secure from those within the city and those outside it through encryption or hopefully more effective methods.
Colorful murals throughout city to create a positive atmosphere including murals that neighborhoods and community houses work on together.
There should be many community parks and community centers where people can meet, take classes, share ideas informally, do group activities like service work, compassion based meditation. Basically the community centers should be used to foster a more interdependent city and help people build meaningful relationships. They should be funded by the government and private donations.
NOW it's your turn...