The pattern for the dresses is a variation off my CocoDress pattern, following the instructions in Aldrich's book for the Stretch Dress on pages 166, 167. I did not make the front panels though, neither the waist shaping.
To sew the seams with a jersey fabric like this, I use a zigzag stitch with very very small width, it seems a straight line to the eye, but it has got elasticity. Next to this stitching line, I zigzag again with wide stitches, and cut the seam allowance just after the zigzag to imitate the overlock. Finally I press the small seam allowance to the side.
For the bottom hem, armsythes, and neck line, I simply rolled the seam allowances inwards twice (1cm each roll), pinned it and machine stitched them with the double needle. The result is perfect.