It looks to me like you're trying to force the 360 rotation with a lot of body rotation and not using enough carving pressure to help with the rotation.
As Cro said, you don't seem to be using a proper setup line into the jump which is the key to building that spin pressure.
Besides Cro's diagram above which goes over your setup carve, you also want to make sure your entire drop in approach is correct.
This means knowing where you do a speed check (if you need one at all), when to start your toeside carve etc.
Here's a blog I did that goes into more detail on that: The Snowboard Jumping Mistake That Every Beginner Makes
Feel free to let me know if you have more questions.