A nation state can either be a Republic or a Principality and either old or new.
An old hereditary state that has been passed down the generations is easy to rule, but taking control and then holding onto a new state is difficult. The difficulty is reduced if you personally supervise it.
An old hereditary state such as a monarchy can be taken by destroying the entire royal family. This is what Alexander the Great did to conquer and hold onto the Persian empire of Darius III. However, states that are used to freedom must be crushed.
For those who are not yet princes, it is possible to rise to become one by carrying out two steps: follow the example of those in the past who saw their opportunities, and be well-armed.
To keep hold of a new state securely, all resistance must be destroyed by using cruel, swift and firm methods, but then benefits to the people should be given gradually.