I pin my pieces together and wher the seams will join,I put a pin through from top to bottom making sure it comes out on the seam.Don`t pin that pin down leave it straight up.Also I set my stitches to 4 or 5 A basting stitch length and sew the first time,if it is correct I put the stitch back down to regular sewing size and resew.If you have to take out and unstitch it makes it easier with the basting stitch.I also do this same thing if it is a Y seam or intricate pieces to sew together.Hope this helps.