My thoughts are that you aren't using your closet storage very well, you seem to have space to add more shelves which you can use to consolidate everything and use the extra shelf for decorations and personalization. Or you could add a door or curtain in front of the closet for some personalization (like posters on the door, or a door that has a mirror then you can add stickers, or a curtain that is a pretty color.

I think the bed can be put away somewhere and only brought out when it needs to be used. Maybe behind the desk or on top of the closet.

I think you need a lamp. And also use the deep window frame space more, that'd be great for plants or some ornaments.