I agree - drapes/curtains would make it cozier.

Green!! A plant on a stand in the corner with the larger picture....some doodad on the coffee table, a plant or maybe a green glass "something"....and titch the beige-ish throw for a green one.

I think there are too many dark pieces. I would say switching the rug for a lighter one, a couple of lighter colored pillows on the sofa, a light pillow on each chair, a lighter ottoman, and a lighter fireplace screen. Also, since the mirror doesn't add much interest in reflecting the stairs, I would suggest hanging something in front of it such as a wreath. I would skip adding curtains because I think it will become too crowded.

move the rug over so the couch is on it..maybe move the chairs in closer? curtains..

A light valance or Roman shade. Add second matching ottoman or take away blue ottoman altogether. Ad lumbar pillow on each of the 2 chairs for color unless the window treatment adds lots of color on that wall. Switch out table lamp for a slightly taller not as wide body made of glass/mercury glass/metal. Hang the framed art/picture on the wall thats sitting on antique record player in corner & replace it with a hanging vine plant. Maybe a glass coffee table the length of your sofa or place the magazines underneath replacing it with a line of votive candles to breakup the wood top surface. Trade out the throw and add more pillows to bring in some shimmering cream colors & texture.

Leggy seating looks better when all four legs are on the rug. Furniture angled in corners intimates that you don't have enough room to properly place it, and it eats up more square footage. Move the antique Victrola to the corner behind the sofa and square it up. Take the sofa to the window area. Place the chairs opposite the window with their backs to the dining room.

a bigger rug that fills the room so all the furniture is sitting on the rug in an accent color; the room seems to consistent.

....a larger lamp on the table between the two chairs, and small accent pillow in each chair. If possible a floor lamp in the corner behind the sofa.

consider squaring up the tall radio ? cabinet between the fireplace and the window wall and adding a pretty big fern.

Nothing on the mantel and a smaller gold or silver fireplace screen that just covers the opening of the firebox.

A basket on the floor by the fireplace for firewood.

Another small picture stacked above the one small square picture to the left of the chairs to fill the wall.....

Pretty glass bowl on cocktail table in a clear glass accent color.

A colorful throw in an accent color on the back of the sofa taking up about 2/3 of the sofa back.......

Fabric roman shades in a pretty cloth pattern that has some of the leather color in it to soften the windows a bit.

Just some ideas to consider as finishing touches for your room.....it is lovely proportions by the way!

Plants. Maybe one by the window. A fig tree or fiddle leaf fig. Those windows are beautiful, it would be nice to add something to highlight it. A painting. On top of the fireplace? Or near the fireplace. You can add a vertical mirror to the left, if you want to place a paining near the fireplace. Find a color that you like, and add it as an accent color to make the room pop.

This space seems to have too many dark pieces. Try adding a white throw to the couch, pillows (with blue, black, and white?), a lighter (and bigger, blue and white) rug, flowing white drapes, a big green plant where the basket currently is, and a larger lamp in between the two chairs. Below is some inspiration to aid you in your dilemma.

You are missing lamps for reading and knitting plus books and magazines to read. There looks like there is room in the corner near the front door for a bookcase--the height would help "lift" the room as would floor lamps.

Just a few tweeks: place a small metal based round table between your chairs and pull them out if possible add a plant to the table, remove the tallish dark piece in the corner and replace with a tall plant or tall light, place stacked large , light colored books under coffee table or something to contrast with the rug if it cannot replaced it with a light rug. Add light colored pillows or throw. :)

Curtains and plants? Love the fireplace!