I’ve finished my DH’s new shirt (you’ll see it tomorrow) and wanted to share another tip that helps me when I’m sewing shirts with lots of buttons (like men’s dress shirts).
I’ve sewn the button holes, opened them up (I like to use a stitch ripper to open button holes).  I’ve laid the shirt over my ironing board and folded the front of the shirt to mark the button placements:

Instead of just marking them with a fabric marker or chalk, I like to insert pins through the button holes, and into the other side of the shirt front (just the front, …read more