What pencils have you been using?
Try different colors on different fabrics.
Try "Sketch and Wash" by General Pencil. Can get it in an art supply store or www.quiltingstencils.com
It is a black washable graphite pencil. Test it first if you do get it. I used it to mark off white cotton sateen and it was almost gone by the time I finished quilting. Many quiters love it
I have also used the Multi Pastel chalk pencils, also made by General Pencil Co. I use white, light grey and have also used the dark grey successfully.