For this Christmas-themed coloring page, I would color the tree in shades of green and brown to represent the pine needles and the wooden trunk. The decorations can be bright pink and purple, alongside occasional gold and silver accents. The princesses should be wearing festive red and gold outfits, each adorned with a unique color pattern. I would make sure to color in the star at the top of the tree in shining yellow to complete the festive look. For the champagne glasses, I would use shades of pink and blue to create a fun, magical feel. Finally, I would use various shades of black and grey to give the picture some contrast and a sense of depth.