An authentic Cartier watch can be identified by the logo and printing, the inscription on the movement, the construction of the case, the feel of the winding stem, and the quality of the dial. The overall weight of the watch is also a clue to the authenticity of the watch, as true Cartier watches are quite heavy. A watch that feels light is probably made of inferior parts.
If a watch is a genuine Cartier, the word "Cartier" is visible after the case back is removed, inscribed on the watch's movement. The case itself should be screwed on, not snapped on. Screws for a Cartier case back are typically on the side or back of the watch. Authentic Cartier cases are beautifully constructed and have excellent engraving.
A Cartier watch's winding stem has a securely fastened cabochon stone. When the watch is wound, the feel of the winding stem is smooth, thanks to the precision engineering.
An authentic Cartier watch can often be identified by the excellence of the logo. The logo appears on the back of the watch as well as on the face. Sometimes a Cartier dial has the name "Cartier" hidden on it. Fake dials are usually fairly easy to pick out. Compare the Cartier logo and script on a watch to authentic copies to help identify a real watch.