I always check the size chart. A size chart and taking a look at the reviews will give me a really good understanding. I also think a lot of shopping sites today have this thing called True Fit, where you can fill in what are all your best fitting shoes, and then it'll just be really smart and tell you what size will fit you best. I would always size up half a size because if you're walking all day, running, then your feet will generally swell a little bit.