My first dirt bike was/is a 2005 CRF450f with an insane amount of after-market parts

. In any event, between the R1 and the CRF, they are completely different beasts and I figured as much. But, I was so worried about it at first; after one day of riding at Hollister, a single crash and a close call (pot hole, almost caused me to go off the hill...would have been bad) and I am definitely no longer afraid of it

.
My only problems were/are jumps, tight turns and downhill turning. I kept hitting jumps hard and I eventually learned to maintain the bike level, but, kept loosing my footing. After reading this, I'm going to start using my knees to grip the bike. That leaves two additional problems, which I've been working on as of this last weekend.
I've seen some improvement, but, I'm still not where I want to be (even as a rookie dirt rider). I've started leaning into ridges with my leg out, ect. But, I've hit a lot of spots where I'm hitting a jump or a bunch of bumps, at the very end, BAM! There is a tight turn, sometimes even a little downhill. I typically lean back, tap the front brake to slow down, a little of the rear if its a close call. But, I've seen some people take the turn like its nothing, swinging the rear going around the turn. So, how do you swing the rear tire? I've done this by just tapping on the rear brake of course, but, it seems like a lot of people are able to do it with their hips, or maybe its something else?
Someone care to assist with this? Would appreciate the help.