What advice would you give to your former high school teachers about preparing students for college?

I would have a lot of advice for my former high school teachers on preparing us for college. I think they should have done a better job with writing in general because a lot of the things they taught us I am now being told is wrong. I think they did a good job in most subjects except English because they just didn't teach us the right punctuation, and the right way to write an essay in high school. Since I have been in college I have learned that high school English teachers weren't correct when it comes to writing an essay, so that is basically what I would give my high school teachers advice on.