How to Gather Fabric When Sewing

I use a similar method to the zigzag stitch using crochet thread this can even be re-used !! Also just to point out when using the traditional method with two rows of long stitches it is much easier to pull up if a)you use the bobbin thread to pull on and b) you sew the two rows closer together I use about an eighth inch and that works well over the years I have sewn hundreds of bridesmaid dresses with very full skirts and sometimes several rows of frills on there too! so I think I can say I have practised a bit!

I agree with Suzanne; the second line is not for backup in case the other one breaks, but to create a flat area between the parallel rows of stitches. If the upper thread tension is released slightly, the bobbin thread can be pulled easily. Also using a stronger thread on the bobbin helps. I use one line inside and the other outside the sew lines; this way the flat area in between is where I stitch the gathered piece to the flat piece. I later remove the gathering stitches that show on the right side.
If you don’t mind the puckered way one line of stitches create gathers, you can use elastic thread on the bobbin.