I typically wear a US 6 in heels and flats (e.g. Toms & Sam Edelman), and a US 6.5 in sneakers and boots (e.g. Nike, Converse, & Sam Edelman).
I got these in a size 230, since they were originally sold out of size 235 at the time. If you're between sizes, you have to choose the larger of the two. These still fit and look great, but they're tight even with thinner socks. Also note that I have slightly larger calves (from running) and there's plenty of room to wear leg warmers with them.
Overall, they're very cute and will go with any autumn or winter outfit! Very comfortable and I think I'll be fine walking around a lot in them. I got the black which is just like in the product photos.