If you don't have a ruler to cut circles, use anything round that will give you the desired size circle. You can use a compass, lot cheaper than the circle ruler. Then make another circle about 1/2" smaller. If appliquing, use this circle to trace on the right side of the circle your stitching line, folding under as you go. For machine sewing, use bluteddi's method. Mostly its just practice, practice. You'll do good.