A good medium for teaching someone how to sew would be a fabric that is easy to work with and forgiving of mistakes. Cotton or fleece fabric are good options for beginners, as they are sturdy and easy to handle. Jersey knit or stretchy fabrics can be more challenging for beginners, so it's best to stick with a basic woven fabric. Additionally, using a medium-weight fabric will make it easier for the student to sew straight lines and practice different stitching techniques.
