Although my original shirt has all of its edges finished with a serger, I chose to use French seams on all the connections between panels. A French seam consists of sewing the pieces together a little into the seam allowance with the wrong sides facing each other, trimming the excess fabric, then flipping the cloth over to sew it again with the right sides facing each other. This second stitch should be just further away from the first seam than the width of the trimmed edges.