When crocheting garments for even and better finished edges I decrease the number of the first chain that replaces the stitch, for example: when crocheting in double stitches I don't make chain of three at the beginning as usual but only of two. This little trick avoids the appearance of holes at the beginning of every second row and makes the garment less prone to change the final measurements. The back of the short shrug is made in double stitches and finished with a row od single stitches - observe, how neat it looks. Besides, will not stretch so much with time.