It's a room or a movie theater waiting for the popcorn. Turn on the darn lights or better? Take a picture in broad daylight. Lose the bed pillow first.

Can't see the whole room so I"m doing some guessing, but I'd flip the arrangement and turn the rug. See layout below

You need to create a color scheme. Given the sectional and window treatments are probably the most expensive to replace, look at changing out the area rug. Find a new one that has color in it that will repeat the color of the sofa and/or blinds. Perhaps, install drapes to frame the window . I would look for a pattern to coordinate with sofa. Other items to add to make the room cohesive: pillows, throws, & artwork. The white object in front of the window, is that a radiator—IF possible, paint it the color of the wall to make it become less of a focal point.
That said, I would recommend a paint color with less of a yellow tone.

I would also try to accommodate both ends of the sofa with side tables..with deep seating this will be the most functional set up ….for people seated elsewhere on the couch…the little tables that overlap the seating and curl under the couch can be placed where needed

If you post a thumbnail sketch of the floor plan, it would help. Looks like a typical NYC/big city apartment. If it is, and the dining area is on the left behind the sofa, add a sofa table with lamps. There may be a way to rearrange the plan if you post the floor plan.

For now, turn the rug. Add a Knoll Saarinen Tulip Coffee Table - oval or round - in white marble top.

If you are considering a lounge chair, keep it simple and a color.

Best Dressed House has great advice.

- Paint the HVAC unit same as walls if you are allowed.

- Add light color curtain panels, ceiling to floor, on brushed nickel simple rods.

- Paint an icy blue, instead of beige as beige sucks the light out of the room.

- Paint the ceiling Benjamin Moore Decorators White (it's a pure bright white)

Color suggestions:

Yeah, my idea is more and better pics.

You might try a round coffee table, along with some pillows, and either C-tables or side tables.

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It looks like you could use a much larger rug, along with some side tables and a coffee table. Below are a few designs we have done for clients. Note the coffee tables used.

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