Although this is only the 4th installment in the 'tips and recs' series, I think it may be the last. Not because the month is over, but because I think I'm out of ideas. 6v6;;; After this, I'm just gonna go back to doing spontaneous 'socially aware' threads.
-So, dark skin...first of all, I'd like to say that I'm not sure why anyone needs to be told how to literally give characters darker skin tones, unless they're just a beginner artist who's never drawn anything but "white" anime girls before (not throwing shade; I've been there...).
Like...surely, if you're a mature, experienced artist, you've drawn a character wearing a leather jacket before. Or any dark, warm-toned object...the color brown doesn't magically become unfathomable as soon as it's applied to human skin; the rules are all the same. Go cool to shade, go warm to highlight, stay within the contrast range of the rest of the piece (every once in a while you see something where all the lighter skinned characters are like p a s t e l s and the one darker skinned character looks like they have their own guest colorist...it's not a sin, it just shows a lack of skill)
-One of the best pieces of advice I've heard about using lighting on darker skin is one that's almost completely useless to me, but I'm sure there are plenty of painters here who can use it: when working with dim lighting, focus on reflection.
It actually comes from a cinematography context, but it's perfectly applicable to static art. So when you have lighter characters, their pale skin tends to "soak up" the available light in the scene; they're just easier to see even if you don't do anything. So you can highlight them by playing with shadows: put part of their face in darkness and the rest will pop even more.
However, this isn't as effective with darker skin, for obvious reasons. When you want to contrast with an already dark color, you get more bang for your buck if you use a light one.
So play with the light instead of the shadow; define the features of the characters with its reflection on their skin. Use different colored light, multiple colors at once, even (it's fun~).
I'd try to explain more, but like I said, I hardly ever even have a chance to use the technique. What I know, I know mostly from watching others.
-But there is one thing I've done myself: experimenting with MAKEUP~
There are probably ten million blogs that will tell you how to do this better than me, but if you want a basic illustration of why it requires your attention:
So I put some 'casual party' makeup on my girl Aren. The first row is optimized for dark skin, the second for tan, and the last for light. You'll notice that the extreme "mismatches" (light-optimized makeup on dark skin, and vice versa) don't exactly look 'casual' anymore...that's my point. You can't just take one character's makeup and slap it on another and expect it to have the same effect if they have different skin tones.
Not that only certain people can wear certain colors...like I said, it'll just have a different effect. If you want to change that effect, you'll have to change some other things. For example, here's the "mismatched" dark-skinned palettes, re-optimized for the lipstick colors:
I'm a little tired, so I think I'll stop here. But there's lots more to talk about: I didn't even mention natural skin coloration patterns, or lightening/darkening as you grow older (at least two of my siblings have done that). But that's what the replies are for, right? ^^