Genetics and nature gave you a lip shape. Cosmetics let you dress your lips up thinner or fuller.
For thinner lips, choose a bold color. Line just inside the edges of your lips.
Fill in with matte lipstick.
For fuller lips, start by drawing a “happy mustache” in concealer above your top lip, extending out and curving upward at each side.
Tap with your finger or a sponge to blend.
Use a soft thin brush like this angled eyeshadow brush to outline just beneath your bottom lip. This will create a false shadow, making your lips look like they protrude farther.
Add a creamy textured lipstick in a nude-for-you shade.
Use a highlight pencil to line above your top lip.
Add gloss in the center of each lip and blend it in.