Anatomy of a Painting

I chose a photo, scanned it in, and put a one-inch grid onto it. I made a similar grid with charcoal on my 3-"x40" gessoed canvas, which is a different shape, so I had to cut off part of the photo image, and add on some on the top (just tree limbs and leaves) to make it work in the new format.
I did a charcoal drawing on the grid. The next step will be the underpainting.