Just wanted to add a note about drawing lines on fabric, pre-rotary cutters and rulers, it was how things were done for precision and accuracy even for hand piecing. You either drew your lines to show your seam lines, or you cut. Of course, pencil is only on the back side. Chances are good if you find a vintage top that there are pencil marks or maybe paper pieces from newspapers or catalogs.
You rarely see a pencil used on the tv shows, but if it is a help for whatever reasons, draw a line! I use it on my mitered borders. I'll put dots at that quarter inch corner for set-ins. Of course I use it for fussy cutting. If it helps, I do it. Because of when I started (just before the rotary revolution), I've never had a moment's unease about using pencil on fabric if I need/want to -- but it is sometimes a new concept to some beginners. Standard No. 2 pencil and maybe a white pencil are all I use.