One of the major determinant of success in what you do is your believe system.
You're what you believe and when you believe in anything you do, you attract more possible ways of making it work out for you because of the power of the law of attraction.
The law of attraction is a law that help us to attract what we believe, think, say and do, as such, if we believe in anything, we'll surely attract more of such things but if we don't believe in anything, we're possibly not going to attract anything positive out of such an event.
So if you're into something that you personally don't believe on it's success, the best thing we can do to ourselves is to quit, because no matter how we try, nothing good can ever come out of it.
To succeed in life, you must first learn to believe in yourself and what you do