One of the things I see often on dark toned skin is a very dark outer lip line. Lip liner is supposed to define the lips, ant to be used as an outliner. When you have dark tone skin try using plum colored lip liner, light purple to plum colored lipsticks, instead of brownish or gold because these colors complement your skin tone.
Dark skin tones often have a natural lip liner of there own. When you find this to be the case with your lips, try skipping lip liner al together. Try peachy lip colors, or lipstains. Have you ever thought about red lipsticks with a blue or purple undertone? There are several brand carrying lovely colors, like Armani, Nars, Laura Mercier and Mac.
When you are seeking for personal advice come and look me up and I will get you Autumn ready.