I've finally understood the different sizes by trying on and buying different shoes from my many trips around the world. This is a guide for Women's Shoe Shopping.
For the Women's shoe sizes I've narrowed it this way using my shoes sizes in different places around the world. I hope it helps all the adult, female shoe shoppers.
USA Size 8.5 = UK Size 6 = Australia Size 8 = European Size 39
Those are the shoe sizes that fit me all around the world