don’t force it
Try to do smooth easy movements to develop form. Speed comes naturally as you improve. I use a mild rotation where I point the center of my chest at shoulder level at one foot. Then stick the other end of the paddle in the water next to the other foot. A simple turn of the upper body to face that foot, and the paddle is near my hip, so I stick it in the water on the other side.
With this technique, I have had my CD Whistler doing 6.3 mph for forty seconds according to my handheld GPS. That is slightly faster than the number reached using the square root of the waterline length times 1.55 formula for so called design speed.
I started learning this going slow and gentle. Speed just appeared after about six hours of paddling time over five or six days. I did spend time just floating and watching wild life, I did not work at this constantly.
Harry