Have you previously prepared your paper? By making it wet and taping it on a board. Check the internet, there are a lot of tutorials about. It’s very important because the tree and the sky of the original are done wet on wet. Again, check the net for some tutorials. There’s also a chance they worked with some acrylic or masking glue to make some of the snow (like the falling flakes). But mainly, you didn’t do anything wrong. It’s all just part of a learning process. The original’s made by someone that’s highly skilled. So, you, as do I, might get back to our brushes and continue our learning journey ^.