Am I the only one who uses my sewing machine for these? I'll be the first to confess that I'm rather 'lazy' when it comes to hand-sewing. I use my machine whenever I can! It's quick and I know it won't ever come apart.
I sew a little rectangle where the two band ends join, and then I put a loop out of the same lace on to use for interchanging bows. After positioning the loop where I want it (over the band seam to 'hide' it) I fold the front edges of the loop back (quite easy since the lace is elastic) and sew through just the band and back of the loop to keep it in place. That also makes it more stable so that the bows don't make the band sag. You just have to make sure that you don't sew through the front of the loop.
Did any of that make sense at all?
The main thing I do different is sizing. 13" is humongous on a lot of newborns. I make 10, 12, 14, & 16 inch sizes so people can figure out the best size for their little one.