Learn how to draw eyes to create a realistic portrait.
Tutorial: How to Draw Lips - 3/4 View http://rapidfireart.com/2016/10/07/how-to-draw-lips-from-the-34-view/
Tutorial: How to Shade Learn shading techniques, tips and tricks for shading realistic portraits.
This may technically be for sketching, but the instructions are the same for filling in missing eyebrows using makeup. You want the brow pencil to look like little hairs so you don't resemble a cartoon character when you're finished!
CHARACTER DESIGN REFERENCES • Find more at https://www.facebook.com/CharacterDesignReferences