I love this and your character shading and coloring is great but I think you have problems with background or than elements in there lack a certain outline or anything defining them. I'm sure that if you follow a couple tutorials on YouTube about that you'll be great at them in no time with some practice of course.

maybe rotate your picture, I don't really see what's going on in this picture

It could be me but, comparing the background to the rest of your drawing skills it's like the background has just been like copied in and you can see it, like the characters have no shadow either and your characters are way more vibrantly colored than the background is which has more muted and calm colors.