I have listened to a bunch of loop lectures and done a few days worth of loop crashes, but never completed one (mostly because I have a problem pulling the trigger when it gets really windy). One thing from those lectures that makes a big difference in the crashes is "riding the boom" - making yourself small and getting your upper body above the boom. Here's a picture of Josh Angulo mid-loop that shows this nicely:
It's mostly pushing down with the front arm. When you get it and ride the sail like that, the landings tend to be a lot nicer.
More pictures from this loop and lots of theory is at boardsurfr.blogspot.com/search/label/loop
I also find the posts on forwards4cowards interesting: forwards4cowards.blogspot.com/search/label/forward-technique
One thing about the Remko video (which is great) that was pointed out to me by Andy Brandt is that the wave in the video comes straight at the windsurfer. That's perfect for loops, but something you don't find often in chop. Some wave spots will have this kind of setup, though.
One of our local sailors actually took loop lessons with Remko in Margarita (where the video was filmed) a while back. He is now throwing loops on both sides pretty much every time he's out there. If I ever grow a pair, I'll copy him