I'm not a great organizer, either, so I have all these scenes I know I want to include in my MG novel and I'm not exactly sure where they're going to fit. But I love Post-it Notes! I wrote scenes or plot points on some Post-its, then arranged those in a file folder so I can put them in some kind of order and see how they'll fit. There are also Post-it index cards you can use if you want to write more on each note. I also bought some butcher paper and cut enough to post across three walls in my guest bedroom. Before I hung that up, I folded it into 30 sections, to match the number of chapters I expect to have. I've written down things I want to track, like story threads, subplots, someone's character development, etc., and when I'm revising I'll use a different-colored marker for each of those things, making a little note on the butcher paper whenever they're mentioned in the book. When I'm finished I'll look at that to make sure I'm not dropping a story thread or to see if I've developed a subplot or character enough.