It looks pretty good except for that ceiling.

i think the only problem is the piano fighting with the fire place. can you turn the piano into the window corner, and create a little seating area by fire place?

i would paint the fireplace wall the same as the others since you do not really want to high light it. maybe paint the fire place out too.

First, I'd have the ceiling attended to and then paint the entire room the greige tone from the horse art (the large patch at the bottom between them.) You might try a lighter shade of greige, cut 50%, for the ceiling since you have light and space. The room has no need of an accent wall with your art. The piano needs to be on an interior wall, so I would place it where the horse picture is, angled so the lid opens to let the music flow out into the room. Hang the TV on the wall between the windows instead of the clock, or hang it above the FP on a swivel/tilt arm so it can be adjusted for viewing. Place your two sofas facing each other 18" away from the coffee table, directly in front of the large window. One will face the window with its back to the piano and the other will have its back to the window. Both can see TV no matter where you decide to put the installation. If TV goes above the FP you can put the sofas in an "L" in the same central location. Place the lounge chair angled by the FP or angled between the windows, depending on the sofa arrangement you chose. Put a large cowskin rug partially under the piano, and a large wool sisal rug under the two sofas to add some needed texture. You can layer another cowskin under the coffee table, but consider a glass and metal one. Save up to do a stack stone FP. In the present TV corner place a game table and chairs, or a pair of chairs and chess table. The blue color from the painting might be nice for the chairs, and for pillows. Roman shades may work better here than curtains, but that can be determined after the furniture is tweaked.

If enough space, reverse piano and couches. Add an area carpet to ground seating area, paint the fireplace brick & mantle a soft white and remove ornaments and plants, placing TV above and 3 tall candlesticks onto lower ledge. Using the horse painting as your staring off point, paint the walls a beige from the painting and if you want more color, paint the wall where you have the horse painting a grey/blue and with the piano on that wall it would be a nice backdrop. May have to move around your artwork a bit. Remove draped curtain on bay window and cover all windows with light roman type blinds. Finishing touches: Replace lampshade with a lager square shaped shade. Decorative items on the coffee table, large wicker basket on dining room table, maybe repurpose tv stand into dining room and use as a serving piece. Hope this helps and enjoy.