I'm a new writer, have been working on a novel length piece of work for the past couple of years, and I have always been the kind of person to just "wing it" and see what happens. After completing yet another draft of this book and feeling terribly disappointed by it, I decided it was time to do some research on how to plan a novel. Since then I've been reading mostly about how to build the plot of the novel and I have sketched out my plot, feeling better about it already than previous versions. This outline of my plot is not too terribly detailed but lines out the main plot points, why they need to happen and how they connect to one another. It also includes what types of conflict the characters face and how the plot point concludes and pushes the characters towards the next one. Over the course of my first few "drafts" I feel that I have developed a pretty good sense of who my characters are and what my settings will look like.
Now I'm wondering, what is the next step in the planning process? I really don't want to just dive in again telling myself that it will all come together because that approach has failed me in the past. What other planning steps or exercises can I do to make sure I have all the framework laid this time to write a good draft? Should my plot outline be more detailed than it is? If so, what else do I add to it without just turning it into another draft? How should I be thinking about my story at this point?