According to Katie Vanderlick, executive director of the Alexandria-Pineville, Louisiana, YWCA, "The average American girl's self-esteem peaks at age 9 and then plummets."
As a young girl my sister struggled with being content in her appearance and friendships. These struggles seem to be univeral among girls in America.
Eventually my sister made some good friends that provided support when she needed someone to talk to. I also noticed my sister's self esteem improved greatly after she started dating the guy that she would marry.
Because women are more qualified to provide relationship advice to girls, I am recommending an article by Kate Conner. Kate offers ten pieces of advice for teen girls. Some of this advice is counterintuitive such as:
"Follow your heart" is probably the worst advice ever.
Kate also challenges girls to see themselves as beautiful.
There is a beauty industry, a fashion industry, a television industry, (and most unfortunately) a pornography industry: and all of these have unique ways of communicating to bright young women: you are not beautiful, sexy, smart or valuable enough.
You must have the clarity and common sense to know that none of that is true. None of it.
Related Link: Ten Things I Want To Tell Teenage Girls
P.S. If I could offer advice to girls in your church's youth group, I would recommend them to start a prayer list with the names of their friends and spend a couple of minutes each day praying for them.