Well I go up a half size. I had the Coach Bonney hightop sneakers in a 9 and was forever in pain. I have a pair of Legacy Striped Ballet Flats in 9.5. They're slightly big but totally workable. Some ladies have said they run true to size but that's not the case with me!
I have a few pairs of coach shoes. They seem to run pretty true to size. I am a 7.5 and they fit fine. I have found that on some shoes I can also fit a size 7 when they are on clearance and don't have my size. Going down that half size really doesn't seem to make much difference for me they aren't tight or anything.
I've found that some of the styles run a little narrow, but the lengths seem about right. I always have to try them on. The boots and heels that I have fit true to size, but the flats and sandals run a tad small.
The Kerrie flip flops are a bit smaller than most coach shoes. I recommend that you go up a size, because they are snug. As far as flats are concerned, I typically go down a half size. Sneakers, wedges, and heels run true to size. Other sandals, boots,and clogs run true to size as well. However, if you have wide feet, which I do, you should try them on first. Some styles are more narrow than others. But even if you do order online, it is no big deal, because you can always exchange them. Good luck with your shoe shopping.