You did well in exposure, it is always tricky with dark black or brown skin to get good color richness with the underexposure needed to keep it realistically dark. Shine is the bigger problem, hard to get away from regardless of how diffused the light is. If one uses manual exposure it is easier to meter and drop exposure 2 stops or so. Our meters want everything middle grey so overexposes dark skin and black suits or tux, for the same reason it wants white satin dresses and snowfields to be grey. Yesterday I shot a few photos of a girl from Brazil who was in the crowd waiting to get into a special event for the World Cup that is being staged here and 11 other cities in Russia. I was taken so by her rich smooth mocha colored skin, but in the sun it was hard to capture the right tone due to too much light so I had her boyfriend hold a map over her head to shadow her face. It turned out really nice, beautiful girl with stunning skin. She had me promise not to let anyone else see them so I can't post one. I spot metered the whites of her eyes and bright white teeth then the darkest tones of her shadowed skin and split the difference for a manual exposure of -2.66 below her eyes.