When I first started to do free motion quilting it was really hard for me to keep the speed of the machine consistent. The more I concentrated on the moving of the quilt that old foot would go to the metal. I think it just takes a lot of time to get the speed of machine going smoothly and moving of the fabric will follow. You might need to just keep practicing. You can fill up a practice sandwich, then change the color of thread on the top and go over it again, that way you can see if you are improving on that pass.
On of the big problems I had at first was also I would forget to put my presser foot down before I started.