I sweat it, meaning I had a project to do so I just learned FCP while trying to finish up a project. I think you'll learn much faster just by doing instead of reading the manual or watching instructional videos.
Start with the basics like capturing footage... which the manual will be helpful, but once you do it for a real project, you'll learn FCP so much faster. Just hit the floor running, or so the cliche goes.
Here's to the Crazy Ones