Your everyday lipliner should be a neutral shade to match your skin tone or mirror your lipstick shade.
Don't be afraid to draw just over the natural line to give the illusion of fuller lips, or slightly inside the lips to downplay a full mouth.
If you have uneven lips use a pencil to correct a natural line by following the contours and creating the shape you want. Be sure to blend it in to avoid a hard line.
Fill in lips with a smooth lipliner underneath your lipstick. This gives greater colour intensity and minimises 'kissing off' your lip colour.
More tips:
Lipstick | Lip Liner | Full / Thin Lips