Uwaaah, I never expected to receive a compliment on my colouring! Thank you very much~
Honestly, though, I just use the standard brushes on photoshop; more specifically, the first row of brushes, LOOOL.
The only thing I do differently with them is change the hardness (setting it somewhere between 75% - 100%; softer for areas like the skin, and "harder" for areas like clothing), and opacity (keeping it at around 25%, and just repeatedly going over areas I want to be darker) of them.
Then, I cheat a lot by using the blur tool to help me blend in the skin a bit better, and a hell of a lot of adjustment layers to fix the colours~ I hope that answered your question well enough!
ALSO, LOOOOL, I ALWAYS HAVE A CREATIVE BLOCK! xD Don't let yourself be deceived by my dA; I only photoshop when I'm explicitly inspired by something, and that's it. U_U