Draw a simplified Christmas tree:
a big triangle. Measure it from the middle line. After this, draw lines across the drawing sheet: from top to bottom, from left to right, from top or bottom to the sides etc.
The tree has to be painted with different green colours (mix them!). The background has to be painted with warm mixed colours. If dry, the lines in the tree have to be drawn with a silver marker, the lines from the background with a gold marker.