Start by applying foundation to your lips and the surrounding area, creating a matte base. This will allow you to draw a sharper and smoother outline with your lip pencil.
Trace the outline of your lips in a darker coloured lip pencil. Gently shade around your lip line, blending the colour inwards towards the centre of your lips.
Now, use a lip brush to smudge your outline further, covering any spaces you may have missed. The trick is to smile, as this will prevent your lipstick from feathering at the edges. If you need to, perfect the perimeter with a little concealer.
Pick a darker shade of lipstick and paint close to the outline you’ve created. You want to create a crisp gradient effect.
Finally, using a small brush, dab on a lighter coloured lipstick at the centre of your lips. Use your brush to work the lighter shade into the darker one, creating even more dimension.