Here is a pattern for a cute Sunbonnet Sue towel topper. We found this in a small local store and found it charming and very country.
You can't see the second row of lace but about an inch or so back from the lace along the edge is a second strip of lace. It helps to define the shape of a bonnet. I think the ribbon hides it or I turned the towel the wrong way to take the pic.
Just cut two layers of the pattern. Lay the lace face down onto the front edge of one layer of fabric. Sew it in place. Sew a second strip of lace an inch back from the first one. Put the two layers face to face and sew around the edge leaving a 2" section unsewn to turn it with. Cut your towel in half or leave whole. Position the towel inside the opening in your bonnet. Sew around the edge of the bonnet and you will catch the towel inside the bonnet when you sew across it. Add a ribbon either when you add the lace or after it is done. Just sew it on by hand if after and if you add it before just make sure you hang the ribbon down into the inside of the two layers.
In looking at the picture I realized she(my friend) sewed the lace farther back than the 1 inch I mentioned. I thought it was part of the lace in the picture. Guess I ddn't look at it very good! I guess sew the lace however you think looks best.