First off, your avatar needs to go...
The harsh light (actually shadow here) does the model no favors, and the 'hot' nose and somebody's shoulder(?) screams "I didn't look at this before pressing the shutter button."
Some of your models look kind of stiff and posed. Posing them is okay, but you have to get rid of the stiffness and get them relaxed and relating to you on a personal basis. You do this by talking to them... a LOT! Yeah, if they were professionals you might get away with just giving them some general directions, but they appear to be amateurs so you are going to have to work at it a lot harder.
At the same time you have to be looking at them in terms of what the lighting is. And if the lighting is harsh, YOU gotta fix it by manipulating it, or 'finding' some good light to put them in. There's ALWAYS some good light around, but you have to learn to SEE it!
The little girl with the ballet slippers is a keeper!