Scars, cuts and wounds are easy to draw since they are little more than a line or short series of lines. The image may be a little more complicated if it depicts a recent scar, however; this means it will have a wider variety of colors and textures. Since scars are part of the skin, the scar itself will need to contour as the skin does in the area in which you sketch it. You also need to keep shadows and shading in mind when sketching the feature. Depending on how much light is hitting it, the scar may not be very visible.
Draw and detail the scarred area, save for the scar itself. It is a good idea to begin shading the area before you add the scar so that you can take the contour and shadowing of the skin into account while you sketch.
Draw the outline of the most visually intense part of the scar. A line may be all you need for this step.
Fill in the center, darker portion of the scar, if needed.
Add stitches to the scar if you are creating a fresh scar. Draw short lines that run perpendicular to the scar; the stitches should look like they are holding the skin on both sides of the scar together.
Draw the outer, less-visible details of the scar. Add light striations to indicate tightened skin by sketching faint, little lines pointing away from the scar.
Color the scar the same color as the unblemished skin around it if you are coloring the illustration. Color the scar, on top of the first layer of color, one or two shades darker than the color you chose for the skin. If it is a newer scar, color it with redder and darker colors. Take contours and shadows on the skin around the scar into account when selecting colors.