I use a similar technique as Pennyhal when I have a fraying fabric. Shorter stitch length on the 1/4 inch seam and then a normal stitch length on a wavy seam in the seam allowance. Having the extra seam slightly wavy seems to stop the fraying. If I sew it straight, then the fabric frays right up to the stitching. Doing it as wavy allows me to go almost to the edge and then back up into the seam allowance. Some people have used a serger on the fraying fabric edge. All that thread can make the quilt too stiff, but sometimes can be the only way to stop the fraying. I have pinking shears but have never tried them on any fraying fabric since I have been quilting. I'll have to try that one of these days. Mostly, once I find out that the fabric frays like crazy, I only use it when I don't have anything else that will do.