I try to use colors that are close to my natural lip color. I have closer to fair than brown skin, but I tan very easily too and I'm originally from Vietnam. Most Vietnamese people have brown skin. Anyways, what I found was that red, brown, and purple looks too dramatic on me. Most strong colors do. So I try to find the milder ones, like the ones you apply on with a brush, and I stick to those. My lip color is peachish pink. I use reddish-pink or light red colors on my lips. I also apply more lipstick as I move away from the outlines cus it tends to have a better look on me, it looks more natural and my lips look fuller too, I guess. :P What you really gotta do is just experiment I guess, heheh. That's what I went ahead and did. ^^ Another tip, when you test a lip color, test it on your palm instead of the backside of your hand. Your palm is usually closer to your lip color.

If you want to make your lips look bigger, avoid dark colours as they have a minimising effect. Line and fill your lips with a lipliner before applying your lipstick. Adding a bit of lip gloss over your lipstick will help draw attention to your lips, or you can use a gloss finish lipstick such as Laura Mercier Stickgloss or Clinique Butter Shine. I do not recommend light beiges for darker skintones, if you want a nude lipstick then use a brown based darker beige or bronze colour. MAC Viva Glam V lipstick is a flattering pink that suits many skintones. The best thing to do is go to a counter and ask for some advice about colour selection. Make sure you ask the assistant to try the lipsticks on you as the colours can look very different once they are on your lips.