1. Be assertive: Assert yourself. Stand up for yourself, your ideals, your principles, and your values. Don't cower in a corner and stay quiet when you see something wrong or someone being mistreated.
2. Be kind to other girls and women. You're in this together. Support your fellow girls and women. You will share struggles, and you're on the same team. Don't stab other women in the back, betray them, be mean, or compete unnecessarily with them.
3. Protect yourself sexually: Not just from pregnancy and STDs, or even from rape and sexual assault, which you can't necessarily protect yourself from anyway. There's probably not a woman alive who hasn't felt sexually threatened at least once. You can't avoid those experiences altogether. But you can minimize them by avoiding situations where you're in unsafe places or in a compromised state of sobriety. And you should only pursue sexual relationships with men who understand the concept of true consent and who love you--or who at least care about you. Because no matter what anyone says about fun, casual sex, or friends with benefits, sleeping with someone who doesn't give a shit about you (and who lets you know it) feels exactly like what it is: shitty.
4. Embrace math and science: There's a stereotype that girls are bad at math and science. Educators have studied this up and down, and it's pretty clear it's a gender and social problem, not an intellectual one. So don't tell yourself--or let anyone else tell you--that you're "bad" at math or science.
5. Love your body: You only get one body. Don't hate it or treat it badly, even when society inevitably tells you that you should. Treat your body with the respect it deserves. Give it nutrition and exercise and use it to swim, climb mountains, ski, and dance.
6. Don't depend on a man to make you happy or do things for you: I don't mean that men aren't dependable, or that you shouldn't have a good partnership with a man. I mean you should know how to do typically "male" things like making fires, changing tires, fixing garbage disposals, operating power tools, etc. And you should never, ever depend on a man's affections (or anyone else's) for your happiness. It's key to self-sufficiency.
7. Understand finances: There's nothing more boring than money, especially the vacant pursuit of money. You want to make a living, not a killing, as they say. But part of making a living is making a budget and taking a basic interest in dry and boring things like pensions, insurance, and investments so you can protect yourself and your future.
8. Kiss a girl: This is kind of a weird one, but it goes beyond sexuality, I think. Yes, there is a certain fluidity to sexuality, arguably more so for women than men. But the experience of kissing another girl is really mind-opening on many different levels. You might be short-changing yourself on those insights if you never do that.
9. Apply for that job and take charge when you get it: Even if you think you're under-qualified; even if you think you're a fraud. Your'e not. Reach beyond what you think you can do in your work life and prove yourself wrong.
10. Travel: I had this same exact wish for Isaac. See the world. Find out how people live from Europe to Africa to Asia and beyond. Understand your privilege. Broaden your horizons. Always.