I lol'd.
Okay seriously it isn't that complicated. You know how to attract a woman post-high school? Be confident. Be successful. It's just in our nature from the time we were hunters and gatherers. Women look for men who will:
1. Be able to provide for them and their potential children
2. Be worthy of passing on their genetics to the next generation
This doesn't mean that you need to support her so that she can be a housewife (not that there's anything wrong with that), but this means that YOU need to have promise for the future. Have a stable job. Have a little bit of spending money. I know, it sounds horrible, but I think it's perfectly fair that women would naturally be more attracted to someone who would be able to support her children in the future. That's the entire point of procreation after all. Just be a good person. Be a nice guy and do good things for her. Even if you're not the most attractive guy, be intelligent. Try hard to improve yourself and women will instinctively find you attractive.
Not all women are like this, but really, don't judge the female sex completely on what you see in high school. We all change quite a bit after our hormones cool down a little.
I'll tell you why I married my husband. He's a great guy, has done great things for me. He's one of the most intelligent people I know and he can hold a conversation extremely well. Even if he isn't the most attractive person unlike the pictures someone posted in this topic, he has women hit on him all the time in his classes because he can keep their attention. He's a good man who has a great future ahead of him. Nothing could be more sexy than that.
P.S. He drinks milk, eats refined sugar, and eats lots of red meat