Take an A/5 watercolor paper, and stick around with adhesive tape on a drawing board. I used Fabriano cold pressed, 300 gr paper.
Sketch the mistletoe, with details, like berries, leaves and branches.
Paint the branches first with shades of green and ochre.
Now for the leaves, with lighter and darker shades and stripes.
If I had covered the plant with masking fluid, I would have had a much easier time with the background. But this time, it has thoroughly given me a lesson. For the berries, I used white guache mixed with a little green and ocher. I also used white gel pen at the end to highlight the outlines.
The finished work, sprinkled with white quache paint, to imitate snowflakes:
Details: