Sometimes the most simple sewing tricks are the best. When folding over a hem or band, carefully snip horizontally into the side seam at the fold or hem line and finger press each half of the seam back in opposite directions. Then fold over the band or hem as normal. This will reduce the bulk in the seam, allowing it to sit much flatter. It works for neck, leg and arm bands as well as regular hems. And the best part - your sewing machine, overlocker or coverstitch won’t groan when it stitches over the hump.
