Personally, I like thick legs on a girl (my blog in my signature is full of girls with nice thick thighs), but there's a trick to making her have strong powerful legs
and making her look feminine.
You should try to make her taller, proportion-wise. Right now, your character is roughly 6 heads tall, which is okay for pre-teens and some taller kids, but if she's a teenager or an adult, she should hit around 6 1/2 heads to 7 heads tall. The average human is 6 1/2 heads tall, while the "heroic proportions" or the super idealized proportions is 8 heads tall. I personally find 7 heads a good number, because it's stylized enough to be appealing, without feeling too realistic or too over-emphasized.
While the basic motion through the body is great, her arms really strange looking. Based on this drawing, I'm not too sure where her arms are connecting from. When you draw, try to lightly sketch in where the shoulders are, and then figure out the arms.
Hands are a little strangely positioned. I can't offer much help to you on drawing hands, other than to just practice them over and over. Spend a whole day just drawing nothing but hands. Don't be afraid to use references if you don't get something. Here's a link to a bunch of hands you might find useful, including things like gripping cylindrical objects:
Photo References - Hand Study.
Keep practicing, you definitely have some strong skills in basic body construction, but there are still parts you need to work on. Good luck!