So, can I learn how to do that too, or do you have to be born with it?
What I do is almost entirely through trial and error. I don't really feel like I know what I'm doing and so I feel uncomfortable calling myself "good".
My process tends to be "Maybe it'll look right if I brighten this part.....no, that's not right....let me try a little darker....no, that's not right.....maybe it just needs to be blended smoother.....no, that's not right......what if I darkened this other part a little first......no, that's not right......" and you do that 50 times until that square inch looks close-ish to what you want. Then you move on to the next square inch!
I feel like my real talent is being patient and persistence not, you know, knowing how to draw.