I was sew some Christmas stocking that of course had curved area and I found that if I held the piece with one hand a few inches away from the presser foot and turn I got a much smoother line than hold next to the presser foot. After I finished I pressed the stocking and then trimmed to about 1/8 in. and sewed around it with a small zig-zag, turned it and using my fingers on the inside I was able to get a smooth edge.