God will place the Holy Spirit within you. The Holy Spirit will speak through you. You do not need to have a prepared sermon to preach. Preach the gospel with all confidence. Speak of your own experience with Christ.
Personal evangelism is a very effective method of reaching people.
You may say that all this is well and good, however, I do not have any special talents in this area. I am lacking the skills needed to teach others about Christianity. We are all given special abilities whether we are aware of them or not. Our talents are there to help us to bring all people into the Body of Christ. Excuses are easy to give but they do not change the fact that as a Christian you have the obligation to minister the Word of God to all those who seek answers.