Measure the biggest use first
Start with the largest vehicle, trailer, piece of equipment, or project that must enter the building. Include approach, turning, door clearance, usable working space, and room for people to move safely around it.
Separate storage from work
Storage can quickly consume a floor area that was intended for projects. Sketch zones for tools, vehicles, materials, equipment, and any dedicated workbench or service area before choosing a final footprint.
Plan the openings with the workflow
Doors should reflect how things enter and leave, not just how the exterior looks. Think about the direction of travel, weather exposure, driveway approach, and whether an opening needs to serve one use or several.