Your eye crease is the point at which the upper bone of your eye socket meets your eyeball. Everyone is different – so some people may have a visible crease in this area whereas others don't. It doesn't matter if you're using eye shadow to define an already visible crease or to create a visible crease, the technique is still the same, and the success of your look comes down to one basic rule: blend, blend, blend.
Use a stiff, pointed pencil brush to pick up the color. Tap off any excess and create a sideways "V" shape on the corner of your eye. Start at the outer corner of your eye at your lash line and extend it out a little bit on a slight upward angle to where your natural crease is or would be.
Pick up some more color, tap off the excess and apply the color from the corner of your eye – where you left off – along the contour, or crease, of your eyeball. Bring the color about two-thirds of the way in.
Use a fluffy blending brush to soften the edges. Start at the outer corner of your eye and move the brush in small, circular motions along the edges of the crease color. Continue moving the brush in circular motions and move it across the entire length of your crease in windshield wiper motions. Continue these back-and-forth windshield wiper motions until you can no longer see any defined lines.
Blending is the key to pulling off a defined crease. Take your time with this and blend until you can no longer see any harsh lines. If you notice your color is not as intense as you want it to be after blending, add more color and repeat the process.