This is a good question. If you read the Prince, you will immediately realize that Machiavelli favors people taking risks, making wise decisions, and acting with conviction and resolute determination. These themes run right through his work.
In light of this, Machiavelli's thoughts on fortune are pretty clear. First, he believe that there is something called fate and fortune, but he does not think that these things should dictate a person's life. Man is responsible. Good rulers will take fate into their own hands and if fate throws something unfavorable, then a good ruler must be ready to resist fate and fight.
In chapter twenty-five, he offers his most pointed words on this topic. He writes: "it is better to be impetuous than cautious, because fortune is a woman; and it is necessary, if one wants to hold her down, to beat her and strike her down."
Of course, these words are offensive, but Machiavelli's words are clear. Take risks and overcome fate and make your own future.