I'm not sure I like the paint color with everything else. I'd consider going with a lighter color, perhaps more in the cream range and with accents in green, perhaps sage green or blue or blue green.

I like the paint color as the green undertone are very soothing. I also really like the stacked stone fireplace--very nice!

I think it's fine other than it needs your personality reflected in it. Get a nice area rub, and some art work for all the blank wall space. Find some knick-knack to go on the credenza and a floor lamp to go at the end of the couch. You can also use throw pillows to bring some personality to the room.

Pillow Decor - Kilim Stripes Blue and Orange 17 x 17 Throw Pillow · More Info

Cerva Pumpkin Ikat Pillow · More Info

EORC T66RD8X10 8' x 10' Area Rug · More Info

Put plants in front of the windows. Good ideas above.

Your ideabooks show monochromatic themes, so here are some textural examples that can add interest along those lines:

one linen panel per side to support the fireplace as a focal point:

Jewelry for the TV console

This because it made me

Urchin Standing Lamp, Brown · More Info

and some artwork , if you hate urchin standing lamps. :)

I think the space is beautiful, you've done a good job with the "bones"! I think you're next decision should be if you want a patterned rug or a solid. A patterned rug will give you lots of colors to accessorize with, now and in the future. Here are a couple of tribal rugs that I found that might work, but you get the idea. I've also included a modern rug, that comes in warmer colors, but that would certainly add color and fun to the room. All the rugs have a touch of gray, to pull in the wall color. You can pull your pillow, artwork, and other accessory colors from the rug. The tribal rugs might be easier to accessorize with, as other patterns work easily with them. The modern rug (i have similar) works well with pillows and fabric with a lot of white/cream background, I used several Ikat patterns in blues and greens for my pillows.

Indoor/Outdoor Colours Area Rug, Rectangle, Light Gray, 5'x7'6" · More Info

NewGeometric Kazak Hand Knotted Wool Red Veg Dyed Tribal Rug H693 · More Info

6'x9' Tribal & Geometric Rug, Super Kazak Hand Knotted 100% Wool Rug · More Info

Your room is narrow, but light and airy so I think the strong color and style of the couch is overpowering it right now. I would not put anything more on the windows for the same reason. They have their own style sort of modern and art and crafts. I would not overpower the area with heavy printed rugs, but maybe a subdued washed look. Use some simple black gallery framed and matted art, black and white or sepia photography. The clean lines along with a hint of the couch colors in the art might be enough to tie the couch into the room.
Think nature, driftwood, the color of Oak trees in the fall or even winter. Make a color pallet like designers do on paper with color swatches of your paint and all the natural beige tones in the room, then think about how to bring more of those into your couch, and less of the couch into the rest of the room...just small amounts. In short, tone down the couch, don't overwhelm the whole room because of the couch. :O

I would have a rug with the same colors that you have in the stone. The window covers seem too dark..would you add maybe some cream linen sheers?
Some lighter pillows for the sofa would help. A nice painting on the left wall..something nature inspired like Birch trees..so still something with creams, greens

Definitely need a rug, which will help keep the wood furniture pieces from blending into the floor as they do now -- for that reason, agree with matching closer to stone (i.e., light) but with an accent color. If you're keeping the couches, then I guess that rust should be at least one of your accents, but you might do another like olive.

I see a rustic mantle, a large clock over it. Definitely an area rug and drapes on both windows wider would be better. A change In wall colour something chosen from the stone, and some colourful art work. Beautiful space. Cushions on the sofa would add to the softness

Erin, you may want to consider TVCoverUps. Framed art or mirror adds to the room's decor, with the hidden TV beneath.

See how EASY it really is:

Hidden Behind Artwork · More Info

Frame My TV with Mirror by TVCoverUps! · More Info

Hidden Behind Artwork · More Info

TV Cover with Panel or Art! · More Info

I suggest that you put in indoor plants to add more life and color to your living room.