I've done this quite a bit, I've currently got 100 8" blocks I need to start assembling. I used a combination of machine embroidery thread, laces and trims. I started with a foundation of muslin and started sewing the fabric on top. I did the decorate stitching as I was assembling so that starts/stops where hidden underneath overlapping fabric. I used tear away stabilizer under the more involved stitches (extra wide or ones that went back and forward longer distances)
I also used a lot of laces and trims for added interest. I was going for a "vintage wedding dress" look with the blocks.