A lot of things determine how successful you'll be: the career you choose to pursue; the company you keep; the things you love doing; whether you possess a burning desire to prove other people wrong. There's no one-size-fits-all prescription. This is good, because we all define success in different ways.
For idealistic INFPs, success often means having the freedom to live a moral, beautiful, and virtuous life. Success in the conventional sense (power, prestige, money) doesn't matter as much as pursuing your passions, expressing yourself creatively, and growing without restraint.