Hi Daniel, as you asked for critique I'm going to be completely honest and say some of these don't work for me...
1) Too grey and I don't understand the 'pose' or her expression
2) Perfectly fine, doesn't blow me away but is a good shot
3) I think the flash is a little too harsh and would benefit from being diffused a bit. Composition is good though
4) Good shot, not much you could do better IMO
5) Flash looks too harsh again for my tastes, also not sure about the positioning of it too as I can't work out if you're trying to add a bit of a seperation light on her hair, or light them... kind of looks neither here nor there and personally i'd have liked to see you use two seperate lights here, one to fill and one to seperate