I'm no pro by any means, but I can throw in some things that were said to me that really clicked. Of course, every rider is different, so that must be factored in also. Much of BP is physically seeing and feeling it. I've learned a lot by sitting on my bike and having somebody adjust my body so I could feel it. As Judy mentioned, they often do that during the lunch session and much is learned. Other things aside from what's been mentioned:
• Try to get your head much over and lower. It should be where the mirror is located and try to touch your chin to the back of your hand... yes, THAT low haha. And your spine should be a straight line from your head and parallel to the bike. Otherwise, you are twisted.
• Half your butt off the bike, and ideally your butt should never be center, you simply move from side to side per turn. Going back to keeping a straight form, I think it's easier to transition from side to side when my body is not "twisted".
• Think of your hip as the incredibly balled joint that it truly is. Ball of your foot should be on the peg and your hip should easily pivot your leg out to create that "triangle". If I'm having trouble easily swinging my leg out, it tells me that something is not lined up right somewhere with my body.
• Arm straight across the tank while off the bike. Arms relaxed too. I had one CR tell me he did "chicken wings" to make sure his arms were relaxed.
Dunno if that's helpful. Like I said, it is hard to write out, and if there is any misinformation in there... anybody feel free to call me out.
Good luck!