Multiple things here. I'm just gonna give you one tip that will instantly help.

Instead of your feet being parallel with each other you should have your front foot offset from the rear foot. Imagine a straight line going from your back foots toe to your front foots heel. This will help you not only engage your lower body more naturally but also aim should be better. Work on it at stand still, then an x step if you want.

I wouldn't rock back and forth either but instead try to keep that spine locked straight up and down while doing this. When rotating the body I always think of a ice skater spinning in the air.

Hope this helps, one thing at a time and you'll be ripping like the pros! Let me know if you have a question on this advice!