I love this project. It is a fun one to teach tint, shade, and tone during the winter months. Students drew castles in Sharpie marker on a separate paper from the background. For the background, they painted cool winter backgrounds using tints, shades and tones of cool colors. They then cut out and glued the castle onto the background. I typically do shorter lessons so this was done in about 45 minutes. With the paint still wet, we used white glue to adhere the castles to the background and it worked out great.
I generally show my students pictures of ice castles from around the world to inspire them. They are encouraged to create their own type of castle and use tints, shades, and tones to make the image more interesting.