¿Cuál es la diferencia entre The knots of your package must be tied tightly. y The knots on your package must be tied tightly. ?Puedes dar oraciones como ejemplo.

As a native speaker, I would not say the "of" sentence. I would say the "on" one. "Of" is a genitive marker. So another way to say that sentence is "Your package's knots must be tied tightly". The " 's " and "of" mean the same thing -- it's just that English for some reason has both. The "of" form can come across as more formal/less casual.

Regardless, I'd say "The knots on the/your package must be tied tightly". It just sounds more natural. Prepositions are one of the hardest parts of learning a language, and every language tends to use them differently. (e.x. in Czech they say "on" in a situation where in English you'd say "in").

Sorry for rambling. You asked a tough question :) maybe someone will give a better answer