Start by placing the tip of your eyeliner at the inner corner of your eye, along the lash line. Slowly swipe the liner to the outer corner of your eye. The more firmly you press down with your liner, the darker your wing will be. If you prefer a thicker wing, retrace your steps a couple of times.
To wing the liner out, angle your line towards the end of your eyebrow. You might have to gently tug the skin at your outer corner to draw a straight line. Most people stop at the crease of the eye, but you can draw your liner out as much as you like depending on how dramatic you want it to look.
Fill in your wing, thickening the curve as you go. Chances are you might mess up a time or two, so grab a cotton swab and start the wing over if you need to.