when stitching curved pieces put the convex peice on top (the out-going curve) the inner curve on the bottom- fold the pieces-crease the centers
match up the two out side edges, match the center crease, then distribute the rest evenly along the curve. stitch a few stitches, stop, raise the presser foot, pivot slightly- keep going.
curves are not hard- just take it slow at first--i'm sure there are some good tutorials that show pics