What fakes do you see most often?
In short: Most fakes in the hobby give themselves away on print, font or stock: the wrong dot pattern under magnification, letterforms that are slightly off, colours that are too saturated, or a card that feels, weighs or passes light differently.
Obvious fakes are glossy, oversaturated and wrong in the hand. The harder ones are closer copies that only fail under magnification or on the scale, which is why I never rely on one test.
Fake slabs and relabelled holders also turn up. The article on spotting fakes walks through the checks you can do at home before you pay for an opinion.
What I check
An authentication opinion covers the print pattern and rosette under magnification, font and text layout against a reference, colour and saturation, layering and card stock, weight and thickness, a light test, and the holographic pattern where it applies. Every check is photographed and named on the sheet; see how I check if a card is real.
Before you buy
If you are looking at a listing, a pre-purchase second opinion works from the listing link and the seller's photos, with the limits of a photo-only review stated. Photographs are kept under the retention and consent policy.