Open up Dictionary of Classical Forms. Borrow studied and known elements from the past and apply them with scholarly flourish. Plaster panels, pediments, medallions, curls, ionic and floral patterns ... stick them self-consciously all over facade, keeping in mind that architecture is poetry in stone. Twirl plaster as window edging till it drips, add delicate Italian balusters to projections to resemble French balcoy. With no door leading to it, it becomes a French balcony that can't be used but don't fret. As long as it's art, it's OK.