When I was in college, I took a creative writing class where the main projects were writing a short story and a personal essay. For the short story, our professor had us write about a decision we'd made. Then he had us write the experience from someone else's point of view and fictionalize it. Then he had us write through to the end of our story before he had us go back and write the beginning. So, when I get an idea for a novel, I rarely start at the beginning. I dive into the action. I have to go back and set it up later, but I just write whatever scene comes to me until the plot starts to emerge. It doesn't take long. If I get stuck, I write background on characters to get to know them better.
It works, but I've been revising and filling in holes and revising the new stuff for the last third of my novel since October. Of course, I took November off for NaNoWriMo, and I always binge read in December. And then, there were all of those fun writing contest the first week in January. But I've been working hard since then. Honest. And I think the end is in sight. I'll let you know when I get there. It's kind of like Magellan finding the East Indies in this clip.
As for my inability to write a first draft from beginning to end, I'm blaming that one on the professor. ;)