I'm just going to talk about the first picture for now.
I love the shirt! The hair's really cute, too!
The upper arms are a little short (making the forearms look really long). Her mouth is really angled, so it makes look like she's pinching her lips. It always seems like you don't really know how to place the arms, so they kind of end up in odd positions, but that's your choice in placement. Another stylistic thing, you always draw the same skirt on every female character. I suggest branching out and trying drawing different bottoms.