1215

First make a list of what you want to do with/in it.  Include storage and room for future growth too.  When I last had a two story place I put a wood shop upstairs and a metal shop downstairs for instance. (blacksmithing equipment does better on a concrete floor than on a wooden floor, especially trip hammers!

 Will you be heating some/all of it?  Will parts need excessive ventilation. (Not knowing where you live we don't know if insulation before it snows means you have 8 months or 1 month to go---or like where I live a year or  3 before the next good snow...)

Not knowing what kind of things you will need to be moving in and out we can't advise on doors, Not knowing your climate we can't advise on a lot of things. Please be more specific!