I agree with what has been said about the big tree. It is too big and too solid. Your eyes are drawn to that big green thing. Don't be afraid of putting another layer of fabric over top of it. Construct your new tree on one of those teflon sheets, you can put some of the building's blocks in the background between your branches and use a lighter green for the leaves. I've had to do thins like that with my stained glass wall banners for church. It will work and you will be happier with the results. You're doing a good job over all.