I think you're making good progress, and I'll say what people told me - use more references.
Just straight copy a pose (do not trace) and try to see where's the difference and why. Take a look at real photos (Google helps) and just change proportions to fit "anime" style better.
You'd quickly notice that some parts in your anatomy are just... off.
With the last one, I think more "floating" feeling would be if you made loose strands of back hair more on sides.
I'm not sure if I see it right, but the front hair are totally straight up? So should the rest of hair, more or less, follow that "action line", wind, gravity, whatever force affects the character.
Some random Goolge search example what I mean with flowy hair - http://www.wallpaperbetter.com/wallpape ... e-size.jpg
There's something wrong with her right arm (left when looking at picture). I think it should be also more up.
Her left leg also gives strange feeling to me. If we're supposed to be looking on it more from side, maybe you could define better knee area.
The same goes to other leg, just two small lines to indicate knee.
Also, general tip: I see that you're making the same mistake as I was with neck/arms - I think it would look better if neck would be a bit more straight, more defined, not just blending in arms. If you just make it a bit wider from head part than by the arms, and made more steep angle between neck and arms, it might look better. It depends on style you want to achieve, but you might think about breaking it in two lines - one for neck line, and draw it slighly more, below arm line, and another line for arm. It might really make a difference in 3/4 view like your sporty type.
Take a look at this: https://i.pinimg.com/originals/ae/7e/2f ... a64c13.jpg
and https://i.pinimg.com/736x/9a/e9/02/9ae9 ... me-cat.jpg
and https://i.pinimg.com/236x/b8/0b/13/b80b ... -girls.jpg
I hope I helped a bit, keep it up!