Books on self development have predominently focused on a positive mental attitude telling you "You can achieve anything you believe strongly enough in." These have lead to some absolute nonsense like "The Secret" and others (I love the ones that claim a basis in Quantum Mechanics) proposing the view that you will recieve back from the infinite universe whatever you send by your thoughts to be amplified by that universe. Of course, if you fail, it is your fault for not having the right attitude -you must have held some doubt all along.
Well, reality is what it is and I'm afraid the PMA nonsense leads to the kind of "irrational exuberance" and "pathological hope" that characterises anyone that believes that reality depends on their thoughts (solopsists) and inconvenient physical truths can be overcome by the right attitude or belief -like those with schizophrenia or religious ferver. This PMA stuff also leads to real depression when you must blame yourself for all the failure that you have experienced and all the failure you will experience.
So, I'm going to give you the truth about success as succinctly as I can: If you are going to try to accomplish anything worth accomplishing you are going to fail. You are going to fail more times than you will succeed. Don't "blame" yourself for this, it is simply the way life is. You must make mistakes to learn and you must expect failures on your path. If you are ever going to succeed, you will simply have to learn to adjust and then keep trying. Perseverence is a necessity here. And there is a good use for PMA when it is done right. Your thoughts don't change the universe until you act on those thoughts -and your attitude is nothing more than how you deal with all the failures and struggles. The proper attitude puts things in proper perspective -you expect failure and you intend to keep adapting and trying until you learn how to accomplish your goal. Persistence will overcome many obstacles. Your attitude is a question of how you decide to feel about the things that happen. Oh, here is another important point. It isn't all about chance and timing either, as even Gladwell's book acknowledges that those who succeed are those that put in the time and effort to be ready when chance drops by. If you are not trying to do anything then no opportunity will ever show up. You must have put in the time and effort to develop your skills before opportunity will come along. Which skills you develop should depend on what you actually enjoy doing since there is no way to know in advance what the opportunity is going to look like and I guarantee that hindsight will show you that you developed the wrong skills for most of the opportunities that happen along, but that isn't the point. The point is that you enjoyed developing yourself.