To finish the rose drawing, you just need to complete the leaves and add some shadows.
Using the same approach of layering undertones, adding lights and then more base color, I've used touches of Dark Brown, PC912 Apple Green, and PC1034 Goldenrod, and PC908 Dark Green to finish the leaves and stem. I've kept them quite light, and actually prefer the finish to the heavily layered bloom on-screen, although the actual drawn bloom has more visible texture and variation, so there is a better sense of unity through the picture. The reds don't scan at all well.
Shadow helps to place the object on a surface. Keep your shading horizontal so that the surface looks horizontal and not sloped. I added a layer of colorless blender first, so that I'd be able to keep the shading smooth on the toothy paper. Then I shaded the shadow in black, and used an eraser to soften the graduation.
