No one has mentioned this, so: I use a stencil with straight lines (mine's from Pam Clarke) with a pounce pad and white chalk. If the fabric is too light for white chalk, I use the white chalk with some blacklight chalk mixed in. The blacklight chalk shows up as fluorescent green under a black light. Both chalks come out with a wiping with a damp clean cloth, or by soaking the finished quilt in water. I used the blue chalk pounce once on a light background and had trouble getting all the blue out, so I'm not a fan of that, and prefer the blacklight powder instead.