Do as much insulation as you can afford, even between rooms.  It's much quieter and warmer or cooler.

Make everything accessible by wheel chair.  You never know what the future holds. But if it's your forever home you or friends might need that accessibility.

Put outlets higher so you don't have to reach way down to plug things in.

What looks big on paper may be smaller when you fill it with furniture.  Don't put any mechanicals in the middle of the house. Any chimney for a fireplace should be on an outside wall.

Speaking of things such as water heaters, they should be next to an outside wall so you don't need power vents if they are gas.

Make a model of the house.  It will reveal a lot more than a drawing.