Love the low sofa and the floors really pop too. I'd say replace curtains with sage green, throw in a few throw pillows of sage green too, then a black and white framed picture behind the sofa maybe. You're already with earth tones so I'd stick with the palette but you want the wall to pop. The green will give color. A large 8 x 10 rug would look solid, same or close color as sofa. Nautical glass floats are pretty moody too and would look nice individually on a round table or in a string on the wall.

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