Peach is WAY better than Supergirl. The background with Supergirl irks me, but I see how it's hard to come up with a background to lineart in such a simplistic pose. Honestly, I don't like the Supergirl lineart, but that has nothing to do with you, so it's hard to comment since that dislike is always just there in the back of my head.
I think you colored Peach way flatter, which is a good thing- the blending in her face looks a bit out of place because of that, though. Generally, Peach is high quality, even though the face doesn't really seem to fit the rest. You're good with finding the right tones for shadows and highlights, though I feel like the deep black shadows in the Supergirl-lineart somehow confused you with this, like you didn't really count them in. With Supergirl it looks a bit too much like you had crisp areas that you then blurred to blend them to me, which really only works when you've got a gradient of more than 4 tones. I'd like to see you coloring something relatively "flat", just letting the seperate spaces be seperate spaces, and something all blended together. You're trying to mix different styles with your coloration and I feel like that doesn't necessarily work before you haven't fully grasped either seperately.