A rug with sofa centered a bit more on the wall. And some art behind sofa, some plants, maybe a couple of velvet pillows.

A plant and/or floor lamp on right side of sofa to help delineate space.

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Start with a rug. No gray paint. Greige or a soft sage. What's with those windows all the wall to the floor. Looks like someone could fall right through them

First decide on a color scheme. Do you want to go with muted earth tones? Or something richer like the deep colors of a Persian rug? High contrast or very neutral with tone on tone? There are a couple of ways of figuring out your color scheme. Look around for pictures of an "inspiration room" that speaks to you. Look through magazines or online sites like Houzz or other decorating blogs. Another route is to find some type of art or fabric or even photo that has colors that you like together.

Woven blinds would be great, but as someone who had them in her last house, I can tell you that good ones are expensive and cheap ones offer no reliable window covering when backlit at night with the lights on. Might as well not be there. You can make fabric liners for the cheap ones if you are handy that way.

Kind of sounds like you are leaning towards a natural palette with wood tones and natural materials. That could be nice . . . You have no art on the walls. Maybe start your decorating by finding some art that speaks to you, even if it is photography, and use that as your inspiration for the style and color. For example, I inherited some Japanese watercolor scenes from my mother, and they provided the inspiration for a color scheme and basic style elements for my dining room where they are hanging. A painting of a beach scene I picked up in an art gallery provided the color scheme and cottage style for my bedroom. A Persian rug I found on sale was the inspiration for my living room color scheme. If you like wallpaper, maybe do an accent wall with a wallpaper pattern you like, and use those colors and that style to start . . .

seems like you have a MCM vibe when looking at the accent chair and dining room furniture, so my thoughts lean in that direction. I would start with sofa and rug and then add from there... I think a geometric rug with a light background and some warm and cool colors so you can move in either direction. add a blue sofa with existing accent chair. just a start... would remove existing coffee table and red side table for new options.

Here is a new layout for your room. I would start by placing the red cabinet as an end table at the end of your sofa. Add two lounge chairs to divide the living room from the dining area. Add a plant and floor lamp in the corner next to the window and keep your MCM chair on an angle as you enter the room. Room with rugs installed to follow.

See how the different color rugs interact with your furnishings and room. In the first photo I made your walls more neutral and less yellow.

This room has your wall the color they currently are painted.

Here is a gray paint on your wall. The color of your furnishings can certainly work with gray. I wasn't too pleased with how the gray area rugs worked in the room.