What about a rug to going in texture and color?

What do you store in the armoire? Can you get rid of the bookcase and shelves, and store their contents in the armoire? Pretty drapery, a rug, and some artwork on the walls would cozy up the room. Lamps and a side table would improve the functionality as a guest room.

A rug and curtains would definitely add color and texture. Is it possible to move the piano to under the window? Or relocate the lower shelves under the window. Add a tapestry or some kind of hanging textile or art to the wall opposite the sofa.

As a guest, I only need a comfortable bed, a comfortable chair, somewhere to put my clothes if staying more than one night, my own set of towels, access to a bathroom........and a room-darkening window shade if the window faces east and/or if the existing window treatment does not give me privacy. A rug is a nice touch as long as it doesn’t make turning the sofa into a bed more difficult.
This room looks like it works well enough for other activities.

Hi all, bookcase can’t go under the window due to the radiator ;). I am thinking to put faux linen curtains & a rug that would go approx. 50cm outside of the bed. Do you think I can go any color ? Or does it have to be grey /green as per the sofa?

You can go any color with rug cos room is pretty neutral.

Have you tried putting the sofa (is it a futon?) in front of the window? It would shorten the room and alleviate the long bowling alley look you've got now.

So, there is a radiator under the window? I can’t see in the photo, so I’ll assume you can’t put anything under the window.

A rug and pillows with color, but not the coordinating blue green. That’s too matchy and would not help. You need some visual interest. Would you consider a small oriental rug in there? It could be moved for the futon when guests come. If you don’t want a lot of color then maybe a sisal or thick jute rug for some texture. That would probably also help with the sound in that room.

Lamps always cozy a space up. Put a small lamp with a fabric shade on the bookcase.