House designing is mind reading…if you are designing your own house, you have to read YOUR own mind…..think…
Specify what you want/need can afford.
Have priorities about… what drives this effort.
You have to educate yourself on the compromises each element forces you to make…
Windows, room sized, cost of windows vs cost of insulation,
Number of SF needed to get bank appraisal high enough that you can get their money.
Foundations and kitchens and bathrooms cost the most…so you have to add on cheap square feet to the drawing, so when the appraisal comes in at x/sf. 300/sf…you have included some cheap sf to build, while evening out the expensive square feet for kitchens and bathrooms.
Then compromises on upgrades… windows small or large, cheap and functional, or triple pane, and good insulators…as many as you can add in to design, or as few as needed to get by.
There are no right answers, but accepting compromise on what looks good inside and out, or what all the people living there want, and you compromise with each other.