Underglaze pencils are a great way to draw fine lines on your pottery. I used underglaze paints for the wide black area, the red rim and the foot. I then scraped a line through the black area with a carving tool and followed the line with a black underglaze pencil. I completed the pattern with some dots between the lines and gave it an allover clear glaze. The pencils come in an assortment of colors and are a bit pricey for a set but you can also buy them individually. Many potters use pencils on the bottom of their pieces to add their signatures.