Use washi tape to hold pleats before sewing. It holds the whole pleat instead of just the top of the pleat.
When sewing corners leave the sewing machine needle down, lift the sewing machine foot, and move the fabric. Then put the sewing machine foot down and sew the next side.
Spray the thread end with hairspray to make it easier to thread in the sewing machine needle.
It’s the worst when your fabric scissors are dull. Use sandpaper and aluminum foil to sharpen the scissors again.