Go to any shooting range, gun store or gun show, and observe how people conduct themselves. And precious few have the proper mindset. This is apparent in their everyday life. Well guys, that sure ain't the way to learn anything. What you receive from any printed source is raw information, and nothing more.
Training has to be structured.
It has to be supervised, and it has to be conducted by someone who is competent and while you are away from all other distractions. The second source is a sign of our times, the Internet. What comes out on the various bulletin boards and forums is also subjective, and a lot of it is just stupid, if not unhealthy. Peruse some of the lists. Yet some of it is very useful in the limited context of information.