Romans 10:14-17 asks several questions. How do does one call on Him in whom they have not believed? How does one believe in whom they have not heard? And how does one hear without someone preaching? Verse 17 tells us that "faith comes from hearing, and hearing through the word of Christ."
Here in the USA, we have such access to churches, Bibles, and other resources to hear and study the word of God. On a personal level we need to be working through studying the word of God, the Bible. Also, we need to be diligent to attend a local church to hear the word of God preached. This is a little more challenging, as it is easy to find a church but it is more difficult to find a preacher who actually preaches the word of God. It's important to find a Bible teaching church, one that goes verse by verse through a particular section so nothing is taken out of context. This is called expository preaching. Topical preaching, another style, can allow for too much opinion and misinterpretation of the a passage or verse.