I am usually in between sizes of shoes (either an 8 or 8.5) and usually size up (8.5) in Me Too shoes. Me Toos tend to have a wider, rounded toe shape, which is a good fit for my feet (not wide feet, but my toes are straight across rather than slanting like most people's feet do.)
My Me Too Swann flats, which have patent caps at the toe and heel, don't stretch much. My Me Too Nini and Legend flats, which are a softer leather, do stretch a little over time, so if they are *slightly* small and aren't rigid patent, I wouldn't be so worried.
Hope that this helps!