Just a wild idea: Paint the wall behind the yellow sofa midnight blue.
And stain the coffee table ebony, it doesn't fit in.
Love the painting above the fireplace, by the way!

The room needs some coherence, a theme or a binding color palette.
Start with the blue, yellow and gold, with some dots of red.
Replace the drapes, look for gold taft fabric, a bit of bling won't hurt.

nice room, and agree it needs pazazz.....remove swags over windows as they are dated & add nothing to the space.

Curtains can soften the harshness of window frames; however I am also an advocate of no coverings if privacy not an issue. Something to be said for letting the outside in.

I love the sofa. Painting above works colour-wise but not size-wise. If you leave there, look for smaller pieces to put alongside to create grouping.

Blue chairs in front of fireplace need to be removed as they are blocking the focal point of room, the fireplace. Suggest placing beside stairs? in corner of room by windows?

Coffee table too small & not right colour. Black would have more impact and a larger size, or two pieces side by side?

For some reason, my eye is telling me that armoire piece by window too heavy. Suggest relocating it to wall on other side of fireplace, and move tray table to window wall.

You may or may not be into plants? if you are, a lovely indoor plant in place of armoire piece would be more attractive by windows. If not, find a faux plant in a large colourful vase/planter to fill that corner.

I can see a folding screen in corner, by window, beside sofa. Check them out online, there are some FAB designs now and they can be extended or not to fit the space, while also adding texture & colour.

Can the piano be moved away from railing? Be nicer look if not viewing back of piano from living room