Here are some books for more information on modesty. I have not read all of them, but I think for the most part they are good influences.
Secret Keeper by Dannah Gresh
A Return to Modesty: Discovering the Lost Virtue by Wendy Shalit
These are about how marketers sell young women immodest clothes.
Packaging Girlhood:Rescuing Our Daughters from Marketers'Schemes By Sharon Lamb and Lyn Mikel Brown
Branded: The Buying and Selling of Teenagers by Alissa Quart
These are about staying sexually pure until marriage.
and the Bride Wore White: Seven Secrets to Sexual Purity by Dannah Gresh
Here is a list of blogs on modesty. I do not claim to agree with the views of all these people. There are many different opinions on what is modest.
This list is by no means exhaustive. I will keep adding to it.