Then, outline the entire border or edge of the eyelid with the darker tone. To achieve the effect you see on the model, you must apply the shadow in such manner that it makes the outer part look thicker and the inner portion much thinner.
At this point, you must take a moment to look at how the colours have been blended.
After doing this, you need to correct any imperfections you might have noticed or fill any parts which need to be filled.
You must make the most out of this second "pass" to highlight the dark tone on the outer part even more.