Planning Longer Plots

There are three basic ways to handle plotting a story, whether it's a short story, a stand-alone novel, or an epic twenty-volume series:  1) You can do it intuitively as you write, 2) You can plan it out in advance, or 3) You can write a bunch of stuff and then arrange it into a plot afterward. (There are, of course, ways that are a mixture of each of these, and whatever way you choose requires flexibility - I think I've met maybe one writer who actually plans in advance and sticks to the...