I am a self-taught editor, as well. I've found that most of the rules I read about end up being very instinctual. If you've watched movies, you're entire life, you've subconsciously developed a FEEL for how they should flow. Trust your instincts, because the majority of the time they are correct.
I tend to worry about gaps in knowledge, too. Technical jargon and specific terms sometimes evade me. A new director I was working with asked me if I knew what a J/L cut was. I had never heard the term before so it made me feel unconfident, but the truth was I had been using them since the first time I cut a scene together because it felt natural to me.
An animator I was working with, said a DP buddy of his was messing around with a 12K prototype at RED. Could he have been misinformed? Sure, but this is RED we're talking about. Oh you like 6K, well how does 12K sound? Ummm...unnecessary?