I use a hera marker for small markings. It works pretty good. I bought a 4' and a 6' straight edge rulers from Lowes. They are metal and exactly 2" wide. I lay the ruler across my quilt in the center or from corner to corner and mark the line (I use Ultra Washable Crayola markers or white chalk for dark fabric). I flip the ruler and line it up on the drawn line and keep marking across the quilt It doesn't take long to mark a big quilt top using this method. Most home improvement stores have them. The six foot is under $15.