From Baidu Baike:
Translation: He who knows how to learn, is not as good as he who likes learning. He who likes learning, is not as good as he who loves learning. (Confucius)
I guess this applies to mathematics as well. The first step to do well in mathematics is to keep an open mindset and try to get rid of any negative thoughts regarding math. Then, slowly proceed to like and enjoy, and even love math. Only then can one reach his full potential in mathematics.
Like most things, there is a nature and nurture component to this. Some people just naturally love logical things including math. Environment like parents and teachers are very important too, a negative encounter in early childhood can easily give a child a bad impression of learning math.