I think your two main areas that you need to improve are convincing that the character is 3D(Perspective) as well as a little anatomy
I had a little time so I went over the girl with the sword (sorry not the best quality because I don't have my tablet)

so first off you tend to make the arms a little long (as well as in the other two images), as a rule of thumb I normally align the wrists at the crotch. Shorten those up her hand should be a little bit smaller as well.
The second thing that could be improved upon would be the legs. They're just a tad too long. Normally they're equal to the size of half the body. Since this is stylistic it doesn't look abnormal and you can really make the legs however long you'd like. I'd say they look fine.
Another thing I'd point out about the anatomy would be the feet. Naturally if she is facing forward the feet should as well.
You can also see that the shorts on her right leg appear to be straight. That line should be curved so you can convey depth. You have to remember that legs are cylindrical in shape so if your drawing a cylinder from an angle and you place a cloth on it, you should see the curve.
Oh and don't forget about the direction of the wind. I don't think I need to say more on that.
Now here comes the tricky part I'm going to attempt to explain. with the way that she stands. You've put her right leg at an odd position. If she's lunging out towards her sword, her body would also be twisting in the direction of that sword. But she's not. To make this look a little more natural (without changing the stance too much you're going to be using forced perspective (other wise known as foreshortening. Good skill to learn but takes a lot of patience) So here I provided another image (also poor in quality, I apologize)

You can see that the thigh was shortened and pulled up a bit more to achieve that foreshortened look.
Overall I think you have a really nice style developing, I agree with @Disciple about references, don't be afraid to use them!
I think you know this, but keep practicing. Not only practice, but know what you need to improve!
Best of luck!