One of the best tricks for balancing scale in a lofty space is the use of molding detail on the walls.
(all photos via my Pinterest "Molding" inspiration page)
Case in point: a living room I'm working on right now is completely out of whack when it comes to scale. The ceilings are ultra high with enormous windows, and while those would normally be wonderful attributes, the space lacks any architectural detail, decor or ornamentation at all in the upper reaches, and the effect is not a good one.
To remedy the situation we're re-working the fireplace surround and adding millwork that will stretch high above the mantle. Take a look at how this trick works to heighten the scale of the fireplace to match the scale of the ceilings and windows.
Dropping an appropriately-sized light fixture into the space is another great trick when working with big spaces ...
As is an extra tall mirror above the fireplace ...
My client's style is a quite a bit more modern than all this, so we definitely won't be designing in such an opulent and traditional style, but you get the idea. A bit of molding can go a very long way!