Also, anticipate seam intersections, they will be double or quadruple thick, and they will cause "a traffic jam." Try to sew around those thick spots, or slow down your sewing machine, and really slow your hand motion down, and go over them slowly.
As a beginner, the sound of the machine will make you want to move equally as fast. DON'T DO IT! Put on some soothing music, and move to that rythem. If you do skip, from a "jeck" or a thick seam, stop and reverse stick to go over what you've just "skipped" and that will be a good solid quilt line (as you've just gone forward, backward, and forward again) and it won't show, unless you point it out to others to critisize.
Relax, go slow, let your machine work hard. Don't sew to long, you'll need to relax your arms and shoulders, and your machine will need to cool off. Clean your machine often, when machine quilting, whether free motion or planned patterns.