I am a beginner in sewing, and one of the problems that we encounter very quickly and can see the difference between the work of a beginner and that of a pro is the regularity of the seam, or keep the same distance between the seam and the edge all along. It is also a tiring exercise for the eyes, and just a moment of inattention to fail it.
This small seam guide should be provided with the machine, it can solve this problem. This loving, steadily, very firmly to the metal part of the sewing machine, and thus serves as a guide to get the fabric.