I sew the two strips together and continue sewing the additional strips (without breaking the thread) so that I have one continuous line of two strips sewn together. When I have that finished, I cut the threads holding all the two strips together, place them in the NEW direction and start back in the other direction sewing the 3rd strip. If I'm doing strip piecing, I continue doing this until all are done. I learned this the hard way when putting my first quilt together--a Twisted Bargello. Unfortunately, because I didn't know this my Bargello "twisted before its time!"