Real meteorites are heavier than they look. Most react to a magnet. They have a dark surface (called fusion crust) and sometimes small round prints on the surface (called regmaglypts).
For iron meteorites, the best test is to polish the inside and use a small amount of acid. A clean cross-line pattern (Widmanstätten pattern) will show up. No stone made on Earth can copy it.
For the safest answer, always send the stone to a real lab. A simple visual check is never 100% sure on its own.