It doesn’t take an expert to know that there are fakes out there but it does take experience to spot them. I certainly didn’t come into the business with a lot of knowledge but I now specialise in 90s/00s Moschino and Versace and can spot many other authentic brands from that era.
My first mistake came when I sold a pair of Moschino cargo pants, new with tags. What I didn’t check was the labels themselves - the English was bad and it should’ve been perfect. The stitching was also quite noticeably bad.
A lot of people assume bad stitching is the first sign of the item being fake but this really isn’t the case every time, well not with clothing. I’ve seen plenty of authentic items where the label stitching inside is wonky. Bags on the other hand - bad stitching is a sure sign they aren’t authentic, especially for high end designer like Chanel, Dior, Fendi etc. Lesser brands like DKNY and GUESS knocked out loads of affordable bags in the 90s/00s though and the quality is noticeably worse than the bigger brands. Internal labels are the biggest indicator of authenticity, both on clothing and bags. Get your eye in on those and you can quickly separate the wheat from the chaff. One of my biggest annoyances is seeing people trying and often successfully selling Dior bags that are so obviously fake.
As for more modern items - I don’t really source them and so lack the experience of whether the labels are ‘good’ or not. There were certainly a lot of dupes (bootlegs, replicas, fakes etc) of Tommy Hilfiger back in the 90s and ironically, some of these now fetch a good price!
All in all, spotting fakes comes down to experience. If you don’t know, ask! If the person can’t provide you with proof of authenticity, then jump on Depop and message someone like me to have a look! (Dm me on @CARRICKO). I’m always happy to help if I can, as are many other verified sellers. Collectively, we have a wealth of knowledge you can tap into. Alternatively and on more modern items, if there’s a Certiligo CLG code, you can enter that into the www.certiligo.com website and they will send you an email for free that states the authenticity (or otherwise) of the item.