It was hard to see where I was going with the darning foot which came with my Janome MC4800. I ordered an open-toe darning foot very reasonably from:
http://www.sewingmachinesplus.com/sewing-feet.php
and it made a great difference. (I'm still not perfect, but much better at FMQ.) Their site shows you, with pictures, what kind of presser feet you need and if you still have questions, they were very helpful to me by phone. I have now ordered four different presser feet for little more than the local dealer wanted for one.