Use a narrow or wide zigzag stitch with the stitches close together, (like a satin stitch). This will keep your raw edge applique from fraying. Learned this in a class and only did it once so far but it seems to work. There are other stitches you can also use if you have them on your machine and it would probably also make a difference if it's something like a wall hanging or a quilt that will be washed a little more frequently. Good luck with your project.