I believe the room needs a color change of the walls as well as the heater with darker colors like I've presented in the Perspective Views.
The floor is the same as well as the dimension of the bed.
The L shaped warderobe is bigger as you wanted but I believe it's going to be hard to find an Ikea product that fits with that dimensions, so i suggest you go with the custom-made one.
The headboard is something special as well as you spend a lot of time reading so lights above your head should be a neccesery with some bookstorage.
The mirror and the wall painting is something that will give the room more visual space.