Not sure if it is too late. I like the piece and the colors. The one thing I see is that you are not using value to your advantage much. All of the foreground is basically one value. The girl and wagon are slightly darker but not significantly.
Also, the background, sky, and trees are really blending together. The pumpkins, scarecrow, and characters pop nicely on the background.
I think this might be why you think everything is getting muddled together. Good luck!