Cut the trees using Pinking Sheers to create a zig zag look on the sides of the trees, which are basically long-ish (new word) triangles. With the house on the background, not fused yet, place the trees, alternating the two different colors. And make sure that you have one on each side that goes off the edge, to create more depth in your scene. You can move things around to get the look that you want.