I'm thinking the girl lacks hip movement. Here is a little sprite I animated keeping in mind that it's meant to be a more girly walk.
(arms a bit long but I think it shows the girl style walk nicely)
Now I'm not entirely sure if it's right but it definitely looks like a girl walking. What really helps sell it is the straightened contact legs, and the less bounce in the walk overall.
Here is another type of walk, kind of high society walk style
another thing you can do is try to exaggerate the butt during the walk. Also I tried to keep the feet as low to the ground as possible so it almost looks like they are sliding that way it takes the stomp effect away. If there is a big gap between the foot being raised and then hitting the ground that creates the stomp effect along with the raising of the body during contact.
*edit*
I decided to try and edit yours and here is what I came up with