The first few times I did FMQ with my longarm, I used good old blackboard chalk - it brushed off easily with a fingernail brush and I was able to try several different times -- I have also used freezer paper on top of the quilt, marking the design with a sharpie, then moving the paper to the back of the longarm and following it like a pantograph. I am getting more comfortable with just doing the FMQ, but it has taken some time.