The 1st one you spun too early and were WAY to backseat.
The 2nd was better, but you no-popped it and were also too backseat
The 3rd still needed to pop, you were a bit more forward, but not quite enough.
When you approach the jump, keep your weight forward, so shins in the front of your boots, knees over your toes, shoulders over your knees...it doesn't matter if you look steezy, learn the trick then add the style once you get it. Turn you arms and shoulders slightly to the opposite direction of your spin to set the spin (just like you were in the video, but keep your weight forward over your boots/toes) Then once you get to the top of the lip, pop up and begin the spin. Use your eyes, remember where your head goes, your body will follow, so keep looking over your shoulder till you spot the landing (this goes for bigger spins, just keep looking till you spin what you want, although you do need to set a bit more too). Once you spot the landing, prepare to land just like a straight air, just absorb the impact, again keeping your weight forward, remember your going from an upward ramp to a downward landing, so you need to adjust for that.
You could also carve into the spin (I'd start doing this once you actually get the 3s down, but it'll help once you get it)...everything is pretty much the same as above, but instead of going straight into the lip, you carve a turn into your spin (so if you spin left, carve a left turn on the kicker before you pop).