@allysa this is a beautiful, wonderfully rendered illustration. The colors are quite harmonious (no pun intended), so not sure that is what needs to change.
Ask yourself what story you are trying to tell with this piece. Why is the she sitting on a roof? What is the purpose or point of her music, or the horn? How is she able to hold that huge horn up with one hand, and not fall off the roof(!)? What led up to this point, or what happens after this point?
Once you answer these questions, and perhaps others, you may find that the way to make this less "boring and unispired" is to find it's story.