Are you hand quilting or machine quilting? On all straight line handquilting, I use painter's tape. On machine quilting lines, I use the little bar that fits on my Bernina foot that lets me follow the first line stitched.(use painter's tape for the first line) For making permanent lines on fabric, I prefer Pigma pens. Always try a marker on a fabric scrap before using it on your quilt. Pigma pens are good on cotton fabric but I have seen them bleed on poly/cotton fabric.