1 - Integration. All things connected to all things. Cities are the physical construction of my and your linkage between home and work, home and the store, home and play, me and friends, etc. etc. A highly interconnected, robust network that prioritizes the quick, easy connection rather than the long distance or regional connection (while still being connected regionally and further afield but only in a way that tangentially interfaces with the local interconnected network, lest those larger connections disrupt local connectivity. To visualize this, think of the way highways tear apart the grid.
Highways deleverage property values so that highest and best use adjacent is either surface parking or non-tax revenue producing.
2 - Accommodation. Once, and only once, you have achieved greater levels of spatial integration, network, the pedestrians begin to emerge. Thereafter, you continue the positive momentum, by creating more attractive places to meet the demand of those pedestrians thereby getting more and more pedestrians. However, any plans to revitalize downtown by only addressing aesthetics of streets, ie street trees, flower pots, and other ephemera, are a waste of time and money without improved spatial integration.
For this reason, pedestrian only streets around the world ONLY work with high degrees of macro-spatial integration, essentially the centerpiece of the entire city and there is still high degrees of density. Many are very simple if not downright spartan in their adornment.
See: Via del Corso, the center spine of Rome. No adornment, no decoration, just high degree of spatial integration with the rest of the city. Any decoration is populated by the the businesses which are populated by the people, which are populated by accessibility provided by integration and interconnectivity.
As of right now, downtown Dallas has neither. The spatial integration is interrupted by various factors including but not limited to the downtown highway loop (which sacrifices downtown for the sake of Plano and places further afield to support 100,000+ people), one-way roads, and roads designed for cars and cars alone (and their various geometries for something nominally known as "safety). This means roads with high turning radii, intersections where cars feel comfortable enough to roll right thru right turns, narrow if not non-existent sidewalks to make room for more cars (which support far less people per square foot of public street than any other form of transportation - meaning less traffic, meaning less real estate value, meaning less attraction).
Car-friendly turning radii. Correlates well with dead areas.
The only place where downtown has some modicum of both is on Main Street and surprise, surprise, it works. However, because of the freeway loop and the other forces interrupting spatial integration, Main Street only works on a micro-scale, not macro, which a road like Ross Avenue has the potential to do.
The space syntax of downtown Dallas, measuring the spatial integration on a micro-level (not city-wide).
Remember: First, interconnectivity then demand drives tax base which drives decoration.