Funny you bring up mistakes...that is often what launched me into understanding what was going on inside the metal. I haven't had the opportunity to do any school for that, it has just been studying on my own as I went. There is a lot of great literature out there. Whenever I encounter something that didn't go as I wanted it to, I don't avoid it, I learn why so that I can either fix it successfully in the future OR so that I can understand why it needs to be avoided in the future.