how can one build up faith

How can a person build up faith? Or is it a talent with which one is born with?

Sri Sri Ravi Shankar: 

You cannot build up faith, you should simply become aware of your doubts and drop them. When you drop your doubts, faith is already there.
A doubt is like a cloud hovering over the mind. Wake up and realize, 'What is this doubt? It is only putting me down and making me heavy. I don’t need it'.
If you refuse to be bogged down by doubt, which you have had in the past many times, then you wake up. And when you wake up, faith is already there.
Faith cannot be built but doubts can be done away with.

There is no end to clarify doubts. You should never go to clarify doubts because when you answer one doubt, it will give rise to ten other doubts. Simply become aware, 'This is weighing heavy on me', and drop it. Then you snap out of it and you come to a place deep within you which is of strength, truth, and endurance. That is called faith.
You would have noticed that whenever you have doubt, you feel weak. When you have faith, you feel very strong; almost invincible from within. So the choice is between feeling strong and invincible or feeling weak.

Doubts are always about something good. We never doubt something that is negative, that is bad. We doubt something that is good. Just this one awareness is good enough to snap you out of it.