According to Machiavelli's view of how to be an effective leader, a ruler should be one who is feared but not hated. Machiavelli states that fear is better than love because love is unreliable. All of the reasons that Machiavelli gives relate to how human nature controls men and drives them to commit crimes in order to reach their goals and satisfy themselves.
Before the organization of Italy as a country, it was broken into city-states one of which Machiavelli called home. He was a Florentine and was deeply concerned with how the political governments of Italy worked because the city-states were almost constantly at war with each another. Machiavelli wrote The Prince when the Republic of Florence fell and was replaced by an autocrat named Lorenzo de' Medici. He wrote the novel in order to gain the favor of the new ruler; however, this attempt failed. Although a failure as a political tool, The Prince remains one of the best works dealing with the power system in a political state.
And I know that every one will confess that it would be most praiseworthy in a prince to exhibit all the above qualities that are considered good; but because they can neither be entirely possessed nor observed, for human conditions do not permit it, it is necessary for him to be sufficiently prudent that he may know how to avoid the reproach of those vices which would lose him his state (Machiavelli 131-138)
This passage implies that one of the main things that a ruler needs to maintain is security and prosperity. A ruler needs to maintain a positive public image and please as many of the population as possible. It is impossible to please everyone whether you are an effective or ineffective ruler, but maintaining the support of the majority of the masses is of paramount concern in being a successful leader.
Machiavelli says that a ruler must be a combination of a fox and a lion. A ruler needs to have the cunning mind of a fox but also needs to have the strength of a lion so that he can destroy anyone who opposes him.