Supply League Observer
What would you say makes the difference from getting promoted from level 4 to 3?
Making no mistakes! The candidates for L3 have the ability to be everywhere, in charge and do everything well. If you watch them, they look like they are the best person on the FOP and refereeing below their level. In the same way that some players look better than the rest of the players.
There is no single item, every referee is different so every solution is different.