Many Christians go their entire lives without being used by God to be the human instrument and means by which a person comes to Christ. My own calling is not as an evangelist, but seeing another human being come to Christ is the most meaningful ministry experience I've ever had.
I once was hired by a church to be the minister of theology, which meant that my job was to teach. They also added to my job description "minister of evangelism." I said I didn't know anything about evangelism. So, they sent me to a seminar to train in evangelism.
The minister leading the seminar talked about how to memorize an outline, how he uses key questions to stimulate discussion, and how there's a pattern to the way in which evangelism is to flow. The idea behind the method he used was to focus attention on the ultimate issue of a person's individual redemption—how can he justify himself before God? Most people will say that they have lived a good life; very few will say that they have been justified by faith alone in Christ alone.
Methods such as these have much to recommend them. They are easy to learn, and they make it possible for people to engage in discussions about Christianity, though care must be taken that one is not simply reading a script but rather is really connecting with the other person.
Ultimately, evangelism is less about the method one uses and more about the message one proclaims. Evangelism, remember, is the proclamation of the gospel—telling the story, announcing the news. Some fear that they don't know enough to evangelize. I say, "Tell them what you do know." Leave the defense of the truth claims to the apologist and hold forth the simple message of the gospel. Anyone who has the ability to speak about three or four simple principles can become an effective evangelist. This is where evangelism programs and training can help.