Adding auxiliary bounce lighting or reflectors is used in weddings
Power point and photo story.
You will need:
Paper (light-medium weight art paper, or computer printer paper)
India Ink (in a bottle with a dropper)
Water in a squeeze bottle (or apply with a brush or cotton swab)
Fold a piece of paper in half. Apply a dot or two of water, and a dot or two of ink.
Fold the paper, and apply pressure with the palm of your hand. Unfold.
Answer:
The easiest thing to do in you situation would be to use references from other drawings or real pictures, and make sure you use a consistent light source. Sorry if this doesn't answer you question but these are some tips.
