Your art style is really cute, and I like the designs of these characters. One thing I suggest is to round the shoulders of the blonde girl more, and broaden them slightly. The arm to her side is a little long, compared to the other one, and you should make the folded arm thinner as it gets closer to the hand, and make her wrist a little more noticeable. You did really well with the green girl's shoulders, I just suggest drawing her other breasts, so it doesn't look off. I also suggest adding layers to her hair, so it doesn't look so flat. Other than a few shaky lines and minor coloring errors, that's all you really need to improve on. Again, I really like these characters, and you did a really good job! Keep up the great work, and keep practicing!