I preface my comments by saying that I don’t know what is considered proper and tsniut for young ladies education.
IMHO, I agree with bymeidel that there should be more education in various tsniut matters.
bymeidel, please note that you don’t even have to go so far as the Shulhan Aruch to find out about dirty media being not allowed. You say in the third paragraph of Kriat Shema that we are not to be lead astray by our hearts and eyes.
Let me also inform you that a man’s hirhurim are worse that a ladies. Therefore it’s very important for a lady to not cause his hirhurim by non-tsniut dress, action, and speech.