They seem a bit under exposed. Maybe 1 stop. The poses are fine, but the focus is a bit soft.
I see the effect you're trying for though.
Most low angle shots project power. In revealing costumes, you may want to be wary of your angle to the camera. Good first effort. The important thing is to just keep at it.
I recommend having a look at GeorgiaCosplay http://giorgiacosplay.deviantart.com/
She does some of the best work when it comes to poses, especially facial expression.