FSC (foundation single crochet) is a great technique to know. You use this instead of a beginning chain, to create a more stretchy base for your piece. This is especially helpful in garments, for top-down construction. You can use the FSC for the collar or the top of a shawl, to keep it as stretchy as the rest of the garment.
I used the FSC in my Appreciation Cowl, to create a uniform edge on both sides of the cowl. If I had used a plain chain when I started the cowl, I would have ended up with the cowl having less give on one side. Below is my tutorial on FSC.