try going to a payless store and wander around in the different size racks and simply locate your proper size, but make sure you have plenty of room in the toes. If it feels close, it will end up cripling you in a short time. They have a decent collection of styles, both heels and flats, but arn't generally the most popular styles, but the good thing is the prices can range from $10 to $25 for a nice pair that look very nice, and a lot of boots if you are into those and have a good selection in larger sizes, I've seen as large as 15 in payless stores. If you like a pair though, besure to try them on and walk up/down the ailse a little just to be sure they fit properly. Sometimes you just need to find the style in a W size and sometimes you may have to go up a size to get a proper fit in the toes. Important especially for heels. Even flats can give you bad bone aches if they are to small, even though your feet slip in easily enough. I got a collection of shoes that seemed to fit when I tried them on but nearly killed me after wearing them a few hours or all day and I am most prone to flats. But yes, the one size larger is a good place to start from.
Terri