I made the background by stamping with the leftovers of cutting out unmounted rubber stamps. I have a whole drawer of these...mostly unused and should be thrown away, but I'm bad at throwing stuff away. I chose pieces that could be cloud shapes and placed them on top of the card I would stamp on.
Then I used an acrylic block with a sticky Tack'n Peel surface to pick the pieces up. I spread different shades of Distress Inks on the rubber and spritzed with water before stamping. The only problem that can occur with this is, that the background part of rubber plates can vary in thickness. These pieces are from Chocolate Baroque, that generally has quite even quality.
I ended up stamping a second generation stamp after heatsetting the first one. This way the sky is more even in stead of stripy. The cardstock is Canson Imagine, which works fine with water. As can be seen, the second lowest stripe obviously was a bit thinner than the rest, as the water droplets haven't been squished against the paper. A nice effect, I think.
I finished of the card with tree stamps I recently bought from Crafty Individuals. This is a combination of two different rows of trees, that have been stamped with Versamark Onyx Black and clear embossed. I didn't stamp quite straight, but was able to fix the image with a black pen.