I'm stepping in here (literally) for Loretta, who is working through the night on revisions.
When I think of fashionable 18th c. shoes, I've always imagined the ones that look worthy of Cinderella or at least Marie Antoinette, pointed-toe slippers elegantly perched on high, curving heels. Here are three examples, courtesy of the V&A: in bright yellow, floral silk brocade, and blue silk satin.
But I learned from the mantua-makers of Colonial Williamsburg that not every 18th c. lady wore high heels. Flats were perfectly acceptable, and just as elegant. Here are two pairs made in the Margaret Hunter milliners shop to match gowns.
The pink pair, above, are quilted silk in a diamond pattern, with matching flat leather soles. The white pair, left, (they, too, would be fastened with metal buckles, removed here) are heavily embroidered with a flowers, designed to peek beguilingly from beneath a skirt. A lady might do the embroidery herself on a flat piece of cloth, and then take the finished handwork to her mantua-maker to make up into finished shoes.
Now that we NHG seen these flat shoes, it's easy to understand how 18th c. shoes evolve into the little flat slippers so beloved by Regency ladies in the early 19th century. Remembering, too, those narrow folding steps that we saw on 18th c. carriages, these flat shoes seem not only stylish, but quite practical as well.