Using all of the above techniques, finish tracing out your composition, keeping as many elements on separate layers as possible. The main advantage of using the computer is that you are free to start making subtle changes to improve your final composition. I have altered the main character making her more prominent, and enhanced the sense of flow by altering her posture slightly.
Now it’s time to give the composition some extra pop by adding shading. Select a shape in your composition – in this case I’m using the head – copy and paste it in front of the original shape and change its colour to black. Paste the shape in front once again, select the Transform tool (E) and rotate the shape until you leave a crescent to the left, select both shapes, and select the Subtract from Shape Area option in the Pathfinder palette. Go to Object > Expand Appearance and reduce the opacity to around 10 per cent.
Certain elements will require different shading technique. Select a more complex shape – in this instance I’m going to use the secondary character’s hair. Select the Pen tool, and following where your shadow will fall on the hair, plot a path accurately along the inside, ensuring there is a decent overflow on the outside, copy the hair shape and paste it in front of your shadow path. Select both shapes and make a clipping mask (Ctrl/Cmd+7). Reduce the opacity to around 10 per cent.