How is it that Peter, James, and John changed the world? Think about it: You and I read their works in the Scriptures, the things they said and did over 1900 years ago. I believe the key, or at least part of the key, to their ability to change the world is revealed in these words,

So when they had brought their boats to land, they forsook all and followed Him (Luke 5.11).

They turned their backs on their successful fishing business, and forsaking all, they followed Jesus. These men became preachers, and so the average Christian may not have to do this, but if you are going to promote His word, you need to be committed all the way.