The Prince

Chapter IX Of the Civil Princedom
This chapter had the best advice for achieving the role as a prince or leader of a country.
"I come now to the second case, namely, of the leading citizen who, not by crimes or violence, but by the favour of his fellow-citizens is made Prince of his country" (24).
This seems to be the best way for achieving this role because the people support you as the leader and to me a great leader is one who is supported by the people.

Chapter VI Of New Princedoms Which a Prince Acquires With His Own Arms and By Merit
This chapter had an idea included that would represent the worst advice.
"The wise man should always follow the roads that have been trodden by the great, and imitate those who have most excelled, so that if he cannot reach their perfection, he may at least acquire something of its savour" (12).
A wise man wouldn't need to follow the actions of previous leaders or imitate those who have excelled. A wise man would have his own ideas and goals to pursue that might not be the same as great leaders of the past but could make him an even better leader.