What is opposite the couch? The piano should not be on an outside wall. Can the couch be shifted towards the window and the piano placed at the other side of it? Agree a couple of chairs. I like the rug. Switch out the orange throw to the light blue from the rug and maybe the chairs blue also. I like the way you have hung your art.

I like your area rug. I'd go with a new sofa in a less dark upholstery that maybe picks up one or more of the paler colors in the rug. Get two storage ottomons, or one long one. I like your dining room light fixture. How about lighter weight drapes on d.r. slider that will hang more gracefully?

I like your leather sofa. Has an eclectic look to it but I'm not one of the everything has to be light and bright people. I'd keep the sofa and add accent chairs that you don't see every day.

I agree piano should be moved. Is there someplace else it can go?

First, I'd pick a function for the room (playing music or games, eatching TV, accomodating lg family gatherings, etc). Then, I'd choose a focal point (window view. couch, piano. faux fireplace--they can provide heat and cozy ambiance), etc. I would then arrange the furnishings to draw attention to that focal point and add any pieces that promote the intended function. I would try putting the piano in a corner on the diagonal, assuming it is not your focal point. I would really dress up the wall or window where the focus should be. I woild either move the rug to under the dining table or at least add a complementary one there. That's my take on it; best wishes for a nice room!

@jck910 Opposite the couch is our wall mounted tv. (Moving the couch off center from TV is not an option for my husband who is an avid movie watcher :) We struggled with where to put the piano because there aren't many options on our main floor. I love the idea of adding chairs- assume you mean to remove the one (rattan) that is already there? My main concern is not overcrowding the space..

@ashtonchic This was the only place we could find that had enough space. (Of course- now I find myself walking around the main floor double checking :)

Really like your rug. I would be looking for a round ottoman.

A slipcover for the sofa might help lighten the look. A more substantial end table for starters.

The ottoman seems a pretty 'clay' color. Does it, and the throw work with rug and such?

SWilliams shows complementing colors, and Emotional and Rejuvenate suggest Dovetail, and similar to your rug.

https://www.sherwin-williams.ca/en/colour/active/color-detail/2307/SW-6620-rejuvenate

Sunset [paint] goes with a Bora Bora Shore... would a medium blue work?

https://www.sherwin-williams.ca/en/colour/active/color-detail/2313/SW-6626-sunset

What's your thought on the pillow of several colors? can you show it close up?

A new light should enter into the discussion, yes or no?

Since piano and sofa are large items, I'd consider coffee table that matches rug's background and window shades...

or blue like your art:

https://www.zoro.com/elk-home-les-revoires-coffee-table-in-navy-blue-3169-127/i/G7358910/?msclkid=09b755502dd71889a134345f6618e939&utm_source=bing&utm_medium=cpc&utm_campaign=PLA_US_Bing_SSC&utm_term=4586131721644236&utm_content=All%20Products&gclid=09b755502dd71889a134345f6618e939&gclsrc=3p.ds

Here's a versatile coffee table that isn't too big, just flexible. Replace the chair with a pair (one of them really comfortable for your movie buff). Use this storage coffee table that also provides a work space. Put the sofa (or a new one) under the window, the piano on the sofa wall and the two chairs at the opposite end of the rug from the sofa, with the TV hound's chair angled to face TV.

Nesnesis Modern Round Lift-top Nesting Wood Coffee Table with Drawers, White/Black · More Info

Consider something with transitional style - so as not to 'clash' with contemporary dining set

Country Cottage Coffee Table Blue Antique · More Info

42" W x 24" D x 18" H. Cottage style dentil work, turned, square legs, distressed finish / Shelf is 36"w x 18"d x 10"h

Solid and straight like sofa, with bit of glass like dining set -

Glass Top Cocktail Table · More Info

Like tv unit, is it like the floor? if so, a blend?

Hull Coffee Table by Gus Modern, Ash · More Info

A bit more of design.. with a less patterned rug:

I really like your rug. I think you should keep it.

I was thinking a rectangular storage ottoman of the appropriate length for the couch.

Monroe Storage Ottoman · More Info

The first thing i would do is to remove the things that are not working…the big lamp by the window…the ottoman..the chair you don’t want …the rug …if you want a change….as it may be overpowering the room and influencing your choices too much….lastly…remove the curtains as they are too formal for the room…then decide how much additional seating you need….with all this done it will be easier to tell ….how big or if a new rug will be needed….and where the additional seating will fit…I would suggest ….to enhance the piano’s presence ….paint the piano wall…a fairly bold accent color….to make it a more modern and interesting feature…the accent color can be selected from whatever color you like in your present or new rug

With the black piano…couch and picture frames …a little black in the rug is a good thing..

This plan will also allow for handy and useful tables and lamps at each end of the couch if needed…and lighter more moveable ottoman/s

@btydrvn Thank you! These ideas are very helpful. Working on removing pieces now and pricing out panel track blinds for sliding door. Thank you so much!