For me, it's easiest to find the center of each fabric first. This can be a bit tricky with bias edges so starch the daylights out of everything first. Fold the piece in half wrong sides together and finger press. This will give you a fold with right side of fabric out. Match up your centers on both pieces and pin there. Pin pieces together working your way out to both ends. You will probably end up with dog ears hanging out 1/4 in on both ends. It looks funky when pinned but then ends up correct when you sew together. Try on a couple of scrap pieces first.