What has helped me with curves is what a friend suggested. Think of the curves as a belly with a stretched out shirt. Pin at the ends and the middle. You will find one way easier. Either piece with the shirt over the belly, hiding the belly. Or piece with the belly over the shirt, hiding the extra shirt. I liked the belly over the shirt, she liked the shirt over the belly. But doing it the same way each time helped over alternating ways to sew.