I took a machine quilting workshop when I first stared quilting. Everyone was asked to bring a large layered square to practice, thin thread no heavier then 60wt and correct needle size, and a machine we knew how to operate. After we practiced on our squares, which most was scrap muslin and batting, the instructor then passed out her sample layered squares for us to use. Our stitches looked great on her samples. Her sample quilt squares had high quality cotton fabric with wool batting. She said use the best for practice. It makes a difference, seeing how nice it looked we stayed motivated and not discouraged.