First thing I want to say is that all the objects and characters in the scene seems to have the right proportional sizes between them.
As previously mentioned, the perspective seems a bit off. That could be used with using a ruler and vanishing points (in this case either 1 or two could be fine). It would make the piece more complete.
The folds in the bed where is the girl's body hint her body shape. Good move. i feel like the other folds are rushed though and could use some work. Especially the area where the folds meet the pillar at the end of the bed. They shouldn't be so harsh and probably not even visible unless the blanket is stretched very hard. Pillows are fine.
The texture on the planks of wood for the wall could be defined better; it feels like it was rushed. The lines denoting the space between the planks should be completely vertical and not bent. We should be able to see where the left wall becomes the wall with the door; the corners aren't obvious.
About the lighting and shadows, you could make some shadows visible and show that there's a light source (ex. light in the corridor and/or the lamp). It would dramatically improve the dynamism of the scene.
Composition wize, there's no objects directly in the middle. That's good.There's no empty spot leaving a big hole but I would maybe add something on the med on the bottom right corner to balance the whole image. The proportions I see of the characters do not seem to be off but I would make the girl's hand slightly bigger. Put your hand on your face open; you'll notice it's bigger than you think ^^. But again, manga characters have smaller hands so it depends what you wanted to achieve.
Images look better when they are scanned before being put on deviantart and a little levels correction can help to make the whites and blacks stand out more.
A good thing to do with drawings usually is to put a framework around it; looks cleaner.
I like the concept. You've already acquired the basic skills, have a sense of organisation of the elements in your scene and you understand how perspective works. No major flaws in term of construction. Good luck and keep at it!