I start with the very bottom layer and use the color fill...usually with black. Next I will go up one layer and color fill it a light taupe or what ever color I choose. for this one I did a light taupe. Next I transform this layer to make it slightly smaller, so I have a frame around the sketch...sometimes I sketch outside the frame..I leave this layer free of sketching and may later use it to add something, but it stays in normal mode.