What tension should I use for cotton?
Cotton requires a moderate tension setting, usually between three and four.
How do you sew stretchy fabric without puckering?
Ensure you opt for the right size of needle for your fabric. Use stitches that will hold the stretch of the fabric – the stitches need to stretch with the fabric, so they don’t pucker and break. If you must sew with a straight stitch, then hold the material taut, but don’t pull it.