I think the one I made had 1/2" seams but most I have seen have about an inch for the seam. Make sure your batting, if you use it is smaller than your squares so it doesn't show so much in the ragged seams
Cut in close to the seam but be very careful not to snip the seam (or another block that happens to be folded in at the time like I did. I had to sew a scrap of fabric over my boo boo)