People want to live in specific locations, or have to in order to find work. This drives land values up as demand increases. Policies can make this worse, but the problem will still manifest itself to some degree. (Potentially as affluent people, especially in suburban areas, buying up more land to create setbacks, or simply buying because they can afford it now, or HOAs setting limits, none of which help density, demand, and cost).
"reduce the costs of construction, particularly residential construction (ie: housing)"
Changing preferences are the best way to address this, yet is likely the most difficult to sucessfully influence. Houses being built today are mostly larger homes, and definitely much larger than the majority homes built generations ago. This means more materials, more labor, more regulation, etc. Now we might be using cheaper materials, or less per sqft, or using tools that increase speed of laborers. But I think this is mostly canceled out by just increasing the size of the house (ie we're growing into our fish bowl).
For a personal example, my wife complains that an 1800 sqft house is too small.