How layering turns a flat corner into a full one
News flash: "cozy" doesn't always mean "more stuff." It means more layers; that isn't the same thing.
A corner reads as flat when everything sits at roughly the same height: art at eye level, furniture at knee height, nothing above or below that band. The fix isn't buying more, it's stacking what you already have so the eye has somewhere to travel.
Take the corner in the photo below. There's a wooden plate propped up to act as a little stand, with a journal resting on it, which in turn becomes a stage for one more curio on top. Beside it, a planter holds one pot, with a smaller pot tucked right next to it. Picture frames lean at slightly different heights behind them. Nothing here is expensive or rare; it's just arranged so no two things share the same eye line.
In the second photo, I did the same thing with books: instead of hiding them on a shelf, I stacked a few flat and used them as a little tabletop of their own, just tall enough to lift a plant and a small frame above everything else on the surface.
That's the whole trick; the heights just don't match. It tricks the eye into reading the corner as deeper than it actually is, the same way a photo uses foreground and background instead of one flat plane. No new furniture required; just look at what you already own and ask which pieces could stand on something else for a minute.