A large part of the knowledge I have gained has come from my own endeavors to seek out truth. Since a very young age I have been a very curious person. I always had questions and rarely had answers. That is probably one of the biggest reasons I love computers, and especially the internet, so very much. Once I started looking for information in this massive network, filled with a large part of the worlds collective knowledge, I finally began to discover answers to my many questions. If I was without this amazing resource, I would be quite clueless in many respects.
The things I have learned range from how many, many parts of human anatomy work (nervous system, immune system, adaptability, bone structure and composition, tissue composition, etc), to how computers work on the lower levels, and even how operating systems and programming languages work. This isn't all. I have found many answers to random questions that come up. Some of my biggest resources have been the Google search engine and Wikipedia. Its amazing how you can just type a question or well-phrased query and find all sorts of answers.
Maybe I am just weird, but I often found school to get in the way of my education. Sure there are those things that I wouldn't have learned without school, and am grateful I did learn, but I found school to be less productive overall than the time that I really spent researching things myself. I cant say I am an expert in everything, but I have gained some good underlying knowledge of a multiplicity of subjects. I have often found the things that I learn to be extremely helpful and good to know. I prefer to know about things myself, rather than just blindly trusting whatever other people say. If I am going to get an MRI, like I just did days ago, I will research into the subject. If I am in some way injured or ill, I am going to look into it. That way I know about it and how to best treat myself. If I am going to gain mad security penetration skills, I am going to find good information resources (like HTS). For some, a teacher could even be a good, knowledgeable resource (but sometimes, in my experience, teachers are quite clueless in the things they are supposed to be expert in).
Sometimes even my family makes fun of me for my obsession with knowledge. I just laugh at myself right along-side them, rather than taking any offense whatsoever. I realize I am kind of a knowledge nerd, truth seeker, or dare I even say hacker, and I know that's just who I am. If someone doesn't like it, that's their problem.
Now, have you ever had an unanswered question? Have you ever had doubts about the truthfulness of information you have received? Have you ever just wanted to know more about something? Try researching it yourself. Here is a great tutorial for learning to learn. In fact at the top you can find a link to Wikipedia, which has an article about autodidactism (self-learning).
Ok, now that you know your resources, use them. Good luck!