Hey! Lovely artwork, i adore the brushwork 
I may have few suggestions for the last picture.
It is mainly about anatomy.
Her arm that holds onto this weapon appears to be longer than it should be (if you "unfold" it and align it with the body, it ends almost where the knee starts.)
I think her neck is also a bit too long considering how the chest plate is built, this top part usually is meant to protect the neck (as far as i know) , hence the neck would be shorter.
And the last thing would be her left leg. While the upper part of it rotated to the side more (including the knee), her foot is facing us. There are two ways u can approach it, i think.
1 - to rotate the entire leg below the knee, placing it at a believable angle of how usually people stand.
or
2 - twist the upper leg with the knee toward the viewer more.
All and all, I love the colours you've chosen and the armor design.
Main pointer will be to draw naked body first before building an outfit on top of it.
Hope it helps and happy painting! 
