As a child, I worked on several marquetry kits, and loved doing it. I still have them - that's how much I enjoyed making them!
The kits were planned like paint-by-number kits, except that instead of paint, there was a stack of varied wood veneers. There was a cartoon of the picture, so the shapes could each be traced onto the woods.
As I recall now, it's worked from the top down, background to foreground. Only the top edge of the first shape was cut exactly. The other edges that would be touched by the next pieces were cut in a rough shape with a little extra wood. Then the next shape was cut similarly, laid on top of the extra lip of wood, and the first wood cut according to the second, not according to the cartoon, for a precision (hopefully) fit. It's very intricate, to say the least, and takes a steady hand.
There is a lot of thoughtful detailing in choice of woods, and the grains are aligned to enhance the design, as in this swirly tree, the grain lines in the snow emphasizing the slopes, and the fencing indicated by a strong grain placed vertically.
The really skinny lines are made by using the veneer end-on.
An image search for marquetry will spark your admiration for the artists who have perfected this beautiful craft over many centuries.