Did you pre-wash your fabric? I find that tends to reduce fraying because it shrinks the fabric and tightens the weave thus lessening the fraying. DON'T pre-wash your cut pieces! That's asking for trouble. You could cut your subsequent pieces a tad larger and use a 'true' 1/4 in. seam instead of a 'scant' 1/4 in. and that will give you a bit more 'wiggle room' with fraying. If you have a zig-zag hole plate on your machine, you might want to invest in a single hole plate to reduce the chance of fabric being eaten as well.