Self-help books are built on the promise of the one thing - that single element that'll change your life, that'll give you happiness, that'll give you fame, that'll give you financial freedom, etc.
Truth is, there is only one thing that you can do to change your life. But it's not a system, a secret, a process, or even a philosophy. Those are just tactics to help along the way.
That one thing is something you can do, today, right now. You can decide.
Successful people aren't blessed with extra-knowledge or extra-talent. Successful people got that way because they decided, long ago, to make a change.
They decided that they were going to do something, even if they didn't know how to do it or where it would lead.
Example: Seth Godin decided to write a blog post every single day, no matter what. He has no idea what blog post he is going to write a year or even a month ahead. But he knows he's going to write a blog post. That was the decision that he made.
Along the way, of course, you'll find the tactics, the philosophy, the process, the system, the principles - the thing you'll tell people in talks, interviews, articles, books, etc.
But none of those things will actually be effective until you make the decision to change - to go in a different direction from where you presently seem headed.