Originally Posted by
Eva Knight
cut a piece of thin cardboard the same size that you want the finished circle to be. Do a running stitch around the cloth circle and pull the thread up enclosing the cardboard in the fabric circle. Press the circle with cardboard inside and then remove it. This should give you a perfect circle.
I do this for circles all the time, too, only I sometimes use two layers of freezer paper (iron them together before cutting) or mylar plastic (make sure you get the kind that can be ironed). Plastic holds up better than cardboard if you're doing a lot of circles.