Have you tried hanging it up or draping it over something and then going accross the room and then looking at it? Distance can sometimes help with perspective.
Also putting it away can help alot.
I noticed on tracy's that she had used a light shade on the bottom left corner and a darker shade on the upper right corners of her "windows", is that what you did? Did you get enough difference that they didn't blend into one another?
Also she seems to have used the neutral color black for the center of her blocks. Did you do that or did you use another shade of blue? And was it a print or was it a solid?