Fit view to object: Numpad .
Hide selected objects: h
Hide unselected objects of the scene: Shift-h
Show hidden objects: Alt-h
Set object origin point (center by default)
Set “cursor” to object corner, than click “Object -> Set Origin -> Origin to 3D Cursor”.
Set object size (dimentions)
Open “Properties” panel (press n key).
Set grid size to millimeters
Set units to millimeters
Toggle “Properties” panel: n