Friendship in the movie Mean Girls only truely exists between Damien and Janice.
Girl/Girl friendships in this movie are shallow and cruel, and unfortunately a pretty (if a bit exaggerated) typical portrayal of highschool friendship. Loyalty is only really exhibited by Janice and Damien, as all the "plastics" and other cliques regularly backstab one another. Girls in this film use the flaws and downfalls of one another to "move up" and inflate their low self esteem.
Girls in this movie are prevented from having meaningful friendships with eachother due to the stringent codes at their school, preventing cliques from mingling with eachother. Guys often also come between girls, as in the relationship between Regina and Cady, preventing them from really being friends because they are competing for the same guy. Looks are also a big factor in girls friendships, as girls often demean the looks of one another to make themselves feel better, and to break down girls they feel are too perfect.
Female role models in this film are really very few and far between.
Cady's mother would be considered a positive role model in this film, she is a college professor and clearly uninterested in what's "normal" and "popular". She cares for her daughter and wants her to make smart decisions. Ms. Norbury would also be considered a positive role model, she is a smart and most importantly she is relateable. She tries to guide Cady not to follow in the footsteps of the "plastics".
Regina's mother is not a good role model for girls, as she tries to be "one" of the clique. She encourages a rule-less househould, and doesn't discipline her daughter for her outragous actions. She fails to show her daughter what it means to be a strong woman. She encourages shallow behaviors and doesn't exhibit any positive ones. Positive role modeling is so important for girls because it gives them a realistic, positive picture of what it means to be a woman, something to emulate that is positive.