The first one that pops up with the selective coloring screams "Yikes!!" Selective coloring is kind of a last resort effect and if done should be with a themed color in mind, but you also missed some areas like around the mouth where color was left that doesn't help the picture.
The poses look ok for your first session. Does your niece use the orange spray tanning stuff? In several of the pictures she seems to be very orange. Keep an eye out for verticals and horizontals, your use of the light pole for adding text is ok, but the pole draws attention to the fact the shot is not level.
Lastly, and I'm sure others will chime in. Post the pictures directly in the message thread instead of a link to your Flickr account. There are many folks who won't go to a link to look and comment on pictures.