A couple of things that might help some:
-teach her to watch the edge of the fabric and the edge of the presser foot (or 1/4 inch seam guide, and NOT where the needle is going
-teach her to let the machine do the work, and not yank and pull and push at the fabric. The machine will guide the fabric through, and a very light touch with her hands just to keep it straight
hope that helps a bit!