I start by coloring the darkest areas very lightly at first, then I color the next lighter areas and darken the previously colored darker areas. I do this a few times over, gradually increasing pressure. Circular strokes work better for me than straight back and forth strokes. To smooth, I go over everything using a white or very light colored pencil with heavy pressure. You need to use heavy paper to do this so the pencil doesn't go right through the paper. I use Strathmore Smooth Bristol paper.