What observation indicates a superior viewing window for Venus when it appears as the Evening Star?

Answer

If it hangs in the sky for two or three hours post-sunset

A superior viewing window for the Evening Star occurs if Venus remains visible for two or three hours after the Sun has set, indicating it is near or has just passed its peak western separation.

What observation indicates a superior viewing window for Venus when it appears as the Evening Star?
astronomyVenüsplanetsky