Well, the first tell-tale sign is that stitching -- the sole should be stitched, not glued, to either a welt or the upper itself. The former is desired for a couple of reasons, though most mid-range Italian shoes I've seen stitch the sole directly to the upper. How do you tell about stitching? Look on the bottom of the sole. Can you see stitching? If yes, then look inside the insole, around the toe area. If you see stitching in the insole as well, you've got a Blake stitched shoe. This is when the sole is attached directly to the upper. If you don't see stitching in the insole, you either have a "Goodyear" welt ("Goodyear" in quotation marks because many claim that most so-called "Goodyear" welted shoes don't follow the real Goodyear procedures) -- where the sole is stitched to a welt as opposed to the upper directly -- or you have a Blake stitched shoe that has hidden the stitches in the insole. If you don't see stitches on the bottom of the shoe, then you either have a channelled sole (hidden stitching), which can be either "Goodyear" or Blake (see above for explanation), or you have a shoe that has glued the sole to the upper (very bad). If you have a Blake stitch shoe with visible insole stitching, then you can be sure by sight that the sole is stitched and not glued. However, if you have either a hidden Blake insole stitch or you have a "Goodyear" welt, then you can't be sure that your sole isn't glued simply by looking at the shoe. I suppose the best rule of thumb is this: If your shoe cost less than $275 retail and you don't see any stitching anywhere (either on the sole or in the insole), the shoe most likely uses a glued sole. That's the very basic initial point about quality construction. As you can see, it's complicated (I've also been working for 16 hours straight so maybe I'm a bit convuluted).