Outline them with lip-liner. Line right along the outer edge of your lip using liner, then line just a bit on your actual lip. This helps the lipstick you’ll apply last, and will prevent it from running on your face, which sometimes happens, especially with darker colors.
Be subtle. Think Kylie Jenner. Don’t give yourself a dramatic cupid’s bow, this not only draws attention to the fact that your lips are drawn on, but also make them appear smaller. Instead follow the natural shape of your lips.