How can I tell if shoes are really high-quality?

At the stitching - on quality shoes it's even, straight, and tight together, not wobbly or with threads hanging out everywhere. The material should feel high-quality, so real leather (not that sticky synthetic stuff) or sturdy fabrics that don't look thin and flimsy. The sole matters too: it should be well glued or stitched to the upper and not come off right away. When you hold the shoes in your hand, you'll quickly notice the difference - good shoes weigh a bit more, feel stable, and don't smell like chemicals from the factory.

The most important thing is how the shoe feels when you're wearing it - if the insole starts digging in after an hour or the material feels stiff and unforgiving, something's wrong. I once bought expensive shoes that looked perfect on the outside, but after two days the heels were falling apart in the back because the construction inside was cheap. Good shoes have a well-designed insole, seams that are actually clean and tight (not just on the surface), and the leather or fabric feels natural, not like a plastic coating. If you can: try them on in person, don't just buy blind online.

Good shoes usually have a continuous insole that's stitched rather than glued, and you can check this by turning them over and looking at the heel - you should be able to see that the sole is really firmly attached to the upper. Here's a practical trick: press your thumb against the heel from the inside, and if it springs right back into shape instead of staying dented, that's a good sign. Cheap shoes feel squishy there and hold the dent. It's also worth looking at the insole lining - with high-quality models, you'll often find more information about the manufacturer and materials than just a generic label.

I'd say that all the craftsmanship details end up being less important than what's already been mentioned - the real test is whether your foot still feels good after a couple of hours! A super practical trick that a lot of people miss: always try on shoes in the afternoon or evening when your feet are slightly swollen, that way you'll notice right away if they're going to pinch later.