A.G.
There are a couple of different things you can do....
1. Try to make plans with the other girls from school, try not to make plans with the already existing clicks bacause she will host an party an still be on the outside. Invite all the girls, or just a few who may be on the outside as well. Talk to the teacher she should know ehere the clicks already are.
2. Try outside activitys, you could even find out what other girls in the class do, i.e. sports softball, soccer, cheerleading, dance, non-sports awana, girls scouts. THere is a lot out there just look around.
3. Individual sleepovers are a great way to start that great bound. Try inviting just one girl to a movie (i.e. high school musical 3, or the dog movie) and then to sleep over. Make plans that will help them make lasting memories.
Good Luck!