Assistance Needed for My New Project, Please!

I've always wanted to write a book. Now appears to be the time, but Ladies, I need your help.

This is the brief:

I'm going to put together a book entitled something along the lines of "Survival Guide for Young Ladies". Remember when you were a teenager? Did you love it or hate it? I know I hated it, but whether you loved it or hated it, if you could time travel back to your old self, what would you impress upon them?

What bit of information do you think most young Ladies could most benefit from? What would you teach your self to do or not do? What do you think are important things for our young ladies to learn or be able to do? What advice would you give them? No matter how trivial or superficial or complex and insightful - I want to hear it all!

Feel free to comment below, but I'd prefer an email to bethanbrunell@gmail.com or a Facebook message. Really looking forward to your input Ladies and seeing as I generally achieve what I set out to, I will, of course, credit your input in the book!