Long and thin
If it is long and thin, then it is not a meteorite
A rock with a high aspect ratio (length/width greater than 3) is not aerodynamically stable and would break apart in the atmosphere. All of the photos below were sent to me by persons who questioned whether the objects were meteorites. None of these things is a meteorite.
Some iron meteorites may have high aspect ratios. Here is the most extreme example that I have found: Taza.