If your space is especially boxy (and you're not a strict modernist!), layer in a circular mirror
(or a group of circular mirrors!), a round end table, or plunk an oval ottoman or coffee table between that sofa and pair of Bergere chairs and watch how it changes the room. Don't stop there, look up! How about a globe or rounded light fixture
like a hanging pendant or half moon sconces? Just remember rounded shapes make a big impact so, a little goes a long way.
Here are a few of my dos and don'ts: