Again take it or leave it:
0:25 did you ask her to yield her hind from you? If you didn't, you should correct it quietly by asking her to move her hind the opposite direction one step. Start with low energy and increase as needed.
0:46 your halt was abrupt with no preparation as to you were halting. They aren't mind readers. Horses do read body language though, and your body language did nothing to indicate your intent.
And you didn't correct her again.
You're leading much better but you're still looking down.
And at 0:48 she does it again.
Better halt at 2:00
Not so good halt on her part at 2:10, and you petted her so now she thinks it's okay to barge past you.
I would have corrected by spinning the rope (not manically, just enough to get her to yield from it) which asks her to back away from it, back to where she SHOULD have stopped. Then I would loop around and try the stop again.
Better halt at 2:16
Not a good correction after she moves though (that correction is more like one that should be used if a horse is leaning/moving into you, or going to bite you, and she was moving away from you, by swinging her butt). It taught her nothing. I would have gotten infront of her, at an angle, and backed her butt up at least 5 feet, then stand still and expect her to do the same. If she didn't, back her up again and try again. Stand for 30 seconds, then move on, once she does stand still.
Good halt at 2:45
Now she's barging into you after, so that's when I'd use the elbow, but honestly I'd snap the lead and get her OUT of your space. Maybe I'd make her yield her shoulders to me, maybe she'd get backed up, maybe I'd send her to the right fast. Barging is corrected by creating space or getting after her.
3:25 she swings her butt again.
3:36 and again
4:00 she'd get whacked and lunged on the spot, as you did, but you do it so messily. The leading hand rope should not be swinging around. You should be less flinchy. Poker face, dude.
4:26 No. Do not get into a tugging match with her, as that does nothing. Continue to lunge her until she's going quietly, then attempt to lead her again.
This is WAY different to lunging into the ground, as that 'trainer' recommended.
She was quiet at 4:30... why did you bop her again? If it's out of petty anger, cut that crap right now. You do not take your anger out on your horse.
I like that you sent her to be lunged again but you standing in the middle like one of those ballerinas on the jewelry boxes is not clear communication. You must have your chest facing her hind end, and your leading hand open for her to move into.
The reason she keeps stopping is because your physical body is infront of her shoulder on the circle. Thus you are blocking her forward movement. You need to physically be somewhere inbetween her ribcage and hip.
5:08, she's actually lunging happily. Why did you start spinning the line again? She made no indication of slowing down. If you want her to pick up the pace you ask once nicely then you get after her. But IMOP she was going nicely and at a good forward pace. You gave her release, but then took it away rudely.
5:15 look at where your body is in relation to hers. You're confusing her by asking her to stop but telling her to go.
5:23, good use of opening hand.
BTW if you constantly use a cue (spinning the rope, smacking a whip) with no breaks, she will learn to ignore it. Then what will you use? Only use it when it's needed. A lot of the time, it wasn't needed.
I'm going to stop critiquing there, because the rest is the same as I've said.
"Strength is the ability to use a muscle without tension"