Here goes my first review!
That scarf is just so harry potter...I like it though it has plenty of details and the style is nice, try to work on giving your drawings some depth, the picture looks like it could be a sticker just on there you know, flat. for example that chimney on his head could have been easily done differently to show it from a 3/4 view so you see two sides of it not just one since she's not facing straight ahead (even though her features are placed like she is I can tell she's not...work on that), same with the books,drawer,table,and TV. I'm not saying that it has to be 3/4, it could be another angle but try to add depth, it's gonna turn your good art into amazing art. Your pieces have lots of feeling and detail and it's great, depth will make them pop and playing around with depth will give you art even more feeling and can help out in the composition of your work.
Composition is something you should look into also, the character is just in the middle with objects on her left and right...not to interesting. This scene could have had a greater impact on the viewer if you the placement of objects/character was changed (again this touches on angle/POV) using composition you can emphasize an object, the ghosts, her head, what ever you think is most important in the piece could be emphasized using the right composition. Mood is another thing that can be emphasized using composition and since you have lots of feeling in your work already it would be awesome with some composition worked in there ;D. Also Composition is used to guide the viewers eye around your piece which can be important for emphasizing key points of your piece.
Another thing is Line Weight. Line weight is SUPER use full for showing depth (which is my main concern with this piece). Her arm that's up could have slightly thicker lines there for making it pop a little more and seem like it's coming out and not touching her body. The ghosts could have a thinner or no outline and that's gonna provide a little texture. point is that lines can be played in order to achieve different effects.
Lintire pretty much covered then rest lol but I hope you find this help full. If you need me to elaborate on anything please let me know I'm trying to help you out here. Good luck in your future drawings!
PS.: Thanks for scouting me! :D