I mainly looked at the fabric you used. In the first photo, I don't think you could have chosen a more beautiful fabric. It gave such depth and dimension . I don't know for sure but it looks like on the first couple of blocks that you painted a small shadow on the backing. I love that. I take my fabric wet it and also dilute fabric paint to give me a nice background. White is a harsh background and doesn't make your applique look as good as a very light slightly mottled fabric. The exception to that is pure crayon colors like you find in the box of 8.
I think you are doing very well on your applique. The only thing that can improve our work is practice. And you have to remember we are our own worst critic.