To start, I want to say that I coach 3 kids teams, so I apologize if I sound like I'm going through simple basics a lot. After watching both videos, I can say with certainty that your swing is garbage. LOL, just messin' with ya.
Seriously though, first things first. Your "ready position". It looks like you need a chair and a beer. Come on man! Your about to hit...you need to look like it. Get that bat back and up. Speaking of "getting it up"....your back elbow.....what did you think I was talking about?!
The swing. Your bat needs to have a level plane to it. Folks who try to kill the ball usually fail and usually have an upward motion to their swing. Also they usually are off balance too.
Weight transfer. If you can transfer your weight, do so, but it should be a fluid motion that begins the hip rotation. Feet close...smooth step forward (toe to 1B)....hip rotation...shoulder rotation...hands through the zone...grip through the zone...barrel through the zone...barrel, handle, front arm align at point of impact....barrel passes in front of hands and pulls the hands, shoulders and hips through to finish. ALL ONE FLUID MOTION.
If you were one of my little guys/girls, I'd start by having you swing from your knees to take the lower body out of it totally. This way you can get a feel for just the upper body motions. Try to think of casting a fishing rod side-arm style. So that everything is straight at the point of impact. Once the upper body part feels right, then take away the upper body by crossing your arms (like you would if you were waiting in line for something) and just do the smooth forward step and hip turn. Then after that gets comfortable, put them both together.
The most important thing is that your swing is FLUID. If you are off balance after, during, before the swing, 99.9999% of the time it is because you are trying to muscle the bat through the zone. Get the swing timing down first, then add more power little by little so long as you can maintain the fluid control and balance.
Almost forgot....your front foot should be WELDED to the ground after your step. Your back foot should be on it's toe and "squashing the bug", meaning staying in the same spot, but rotating as if you were squashing a roach.