Really easy method...take a coffee filter - press it flat - stitch to right side of fabric - trim (I usually use pinking shears). Slash the coffee filter and pull the circle through - the slit. Press - trim the coffee filter to about 1/8 inch and top stitch it to the background square/quilt top. This works and is an easy time saver. I used this to make a queen size top - and created attic windows with the circles sewn to background squares.