just a quick note on skin tones.
i like your start, by the way. showing real intention on the learning side of art.
but back to skin tone. if you study it carefully, you'll find that skin is not just made from pinks and earthtones. there are underlayers that bring depth to skin, so as to not look like it's painted on with makeup. i'd recommend first laying down the highlights and shadows monochromatically. i've seen many people use a green wash underneath skin tones, and seems to work really well. once the darks and lights are laid in, then you can go with more localized color.
remember, you're not trying to paint skin, you're trying to pain "light".
Hey dog. . . . did you see the size of that chicken?!