John Huston said that great directing is in the casting. In fact he stated "80% of directing is in the right casting". having said that, none of that will matter unless you have a good script to shoot. As a mere observer, I also understand that simplicity works better, unless you're making a music video. Traditionally, I think the best films are about people and their stories, so getting the right actor is the most important thing, once everything else is right.
That being said, I need to learn how the technical aspects of movie making work, which is important, but I don't think the latter matters, if people don't truly understand what cinema is. Martin Scorsese simplified everything to me when he said: "The biggest challenge in cinema is getting what's in here *points to his head* onto the screen, that's it."
So, learning the technical aspects of filmmaking is crucial to understand how it works...once these things are learned, then practice them. I think that helps avoiding silly mistakes.