Don't feel too bad about not getting the rocking motion thing. I've also tried different times over the years, and still am not able to do it well. I keep going back to it from time to time. When I do hand-quilt, I use a sort of stabbing, up and down motion, as you might do for certain embroidery stitches. I work at keeping my stitches consistent, and that's it.
I do a lot of machine quilting, but sometimes it's nice to sit in a nice comfy chair and do some hand work.