I did a lot of things right, surprisingly...and am pretty happy with it all.
Things I wanted to do, the village tied my hands, so I live with what I could place.
I suggest you know how big you can build, and build it based on what you can get away with. Go into debt and wish for as many things as you want....if you are young enough, you will afford it in the long run and increase your property value...and taxable property value will increase too, unfortunately. It is amazing how time causes the soil line to increase around buildings. Between sink-age and particulate matter in the air, 50 years in the future, your building can actually be lower than your ground....build it high and dry! Make sure the building can support a future lift.
In hindsight, collecting gutter rainwater for irrigation and storing it underground in a cistern would be very handy since our water rates for Lake Michigan water continue to skyrocket. Insulate with styrofoam and never worry about the insulation breaking down from moisture, rodents, or gravity. Plan for a security system, both passive and active.
Bolster deadbolts, install window bars, cameras, etc....as you see fit.
Good luck!