I admit, if you look at my first book drafts, you'd be bored out of your skin because I didn't understand the basics of plot. In fact, I had been writing for something like six years before attending a conference where I heard something that really helped me understand what I needed to do to make my stories work.
Since then I've read a lot of books, blog posts, and articles on plotting. Most recently I attended a workshop where Dan Wells gave his theory on plotting--and luckily, he's posted his presentation on Youtube for anyone to see. This is a 5-part presentation, and I've watched parts of it multiple times as I've worked on new stories, reminding myself of what makes plot great in a quick and dirty explanation (compared to reading a book, anyway!) that really helps put it all in perspective. Make sure you click through and see the other four parts!