I trimmed some of my Altenew watercolor paper to an A2 sized panel and broke out my Altenew pan watercolors. I began by painting random colors, one color at a time.
I ended up with a patchwork of different colors on my card panel.
For the stars, Kristina recommended transferring the water spritzed white paint to an acrylic block and flicking the paint off the edge of the block with the paintbrush. It worked incredibly well and I'll definitely be trying that again.