Being humble means being completely aware of your greatness and achievements but also being aware of the fact that whatever you have achieved you did so because God gave you the abilities and the strength to be able to do it. That means that a person who is an extremely successful businessman, for example, should not carry himself as if he is more important than others simply because he is successful. He must internalize the fact that his success lies with the fact that God gave him that success and how he can best use it. I once heard an extremely successful businessman (he counts his wealth in hundreds of millions of dollars!) say that he doesn't look at himself as being very good at business it is just that God put him in the right places at the right times.