Since we are mostly on our own when it comes to education and our learning depends on our own initiative, it becomes critically important to understand why anyone wants an education in the first place. This is especially true for those of us who reject the notion than a degree should be an indicator of status. So here's what I have learned is important to know.
Reading is still the biggie. It's the ultimate intellectual shortcut--in a few hours you can read a book that may have taken the author a lifetime of learning to write and when you are done, you know roughly as much about the subject as the author. If you can extract good information from books (and now the internet) it doesn't make a bit of difference how poor you were or how crappy your schools because you can still find out the important stuff on your own. Even better, reading is self-reinforcing--the more you read the better you get at it.
Writing is still important but these days, other methods for getting an idea from your head to another's should be learned as well. These include illustrations, charts, schematics, and video production.
Knowing basic math is essential to understanding your surroundings. This does NOT mean you are a failure if you never quite understand calculus. But you should know the difference between a million, a billion, and a trillion, how to calculate and understand percentages, how statistical sampling works, and the rest of the skills one must have to extract meaning from news, government documents, and campaign literature.
Knowing history is critical. If you don't know history, you must think that that world was mostly complete (transportation, buildings, governments, etc.) the day you were born. This is the perfect prescription for infantile thinking. Worse, if you don't know how the world got the way it did, it is impossible to understand your point in human development. If you don't know where you come from, you cannot know who you are--and if you don't know who you are, you cannot know where you are going. Historical illiteracy leads to personal aimlessness--every time.
There is a Predator lie that claims that "educated" people don't have to understand tools. And while everyone doesn't have to operate tools on a daily basis to understand the lessons that technological gracefulness teach, it is also true that people who never learn to use tools and in fact, look down with disdain on those who do, are usually confused about very basic issues. Not surprisingly, technological illiterates cannot contribute much to a discussion of technology-based issues like Peak Oil or climate change.