Start with a blank field on the edge of a growing city. The tempting plan is a grid of towers with a park in the middle, because that is what renders well. The plan that ages well looks different, and its logic is mostly about time.
Streets come first. A district with narrow blocks, eighty metres or less, gives pedestrians four ways to reach the same place, which spreads foot traffic instead of concentrating it. Wide arterial roads do the opposite: they move cars quickly for twenty years and then become the barrier that splits the neighbourhood they were built to serve.
Second, mix the uses. A zone holding only offices empties at six in the evening; a zone of only flats empties at nine in the morning. Shops, workshops, clinics and homes on the same block keep the pavement occupied across the whole day, and occupied streets feel safe without any additional supervision.
Third, design for heat and water before designing for beauty. Trees planted along the sunny side of a street shade the pavement in summer; permeable paving lets rain soak away instead of overwhelming drains; a small square every few blocks gives residents somewhere to sit that is not a cafe. These choices cost little at the planning stage and are almost impossible to retrofit later.
Fourth, decide who maintains what. A fountain is a delight for two years and a liability for twenty unless the budget for pumps and cleaning exists from the beginning. The most common failure in new districts is not ugliness but deferred maintenance.
None of this requires new technology. It requires deciding, early, that the district will be judged in thirty years rather than on the day it opens.