Controlling cost in the design stage is a critical component in designing and building your custom home.
As a homebuilder/developer, and home designer, we have an advantage over other architects and home designers in that we build (and sale) our homes. That means the home design must be great, the construction/materials are cost effective, and the price point is correct.
Price is a component on the type of home design (single story versus two story, etc), and the square footage. Then, the cost of the upgrades are added.
Most labor and material cost will be based on square footage. A secret in great home design and price point is to control the square footage (no wasted square footage) and design the house in a manner that creates the feeling and ambience of a larger home. Bring in the outdoors through large windows and exterior spaces is a good example.