What are some ways of telling the difference between a fake Rolex and a real one?

Other than the perpetual motion and the green stuff on the back.|||Put the watch next to your ear. If you hear ticking, it is a fake. Quality watches, including Rolexes, will never give any sound no matter how hard you try to listen. Another option is to break the glass as Rolexes won't break. They are made of a sapphire blend material. Listening to the tick is the safer way of checking. :)