Practice shooting my niece....

Poses look really unnatural. Also, watch your flash. Other then that, photos are sharp and WB is good.

Photos are sharp, but look boring because of the composure and too much flashes, I guess

Yeah it was really hard to pose her, a few shots in she was already tired, I was simply trying to use a couple of flashes and really one of my first shots at strobing...

Dial back on your flash. The exposure on her is too bright and the flash sems pretty harsh. Either decrease the power output or close down your aperature. Not a bad start though!

She's a very pretty girl, and I like the dress she's wearing. The colors are quite nice.

I think the flash is a little hot as mentioned. In the 3rd shot the shadow is not good on the face.
I like the poses, a few of them look stiff but some are fine. The second to last is nice as well as the one on the tree with her hair blowing.

With kids I think it's good to tell a few jokes and play to loosen them up and you'll get a natural smile and a bit more relaxed.

Overall you are off to a great start.