First you have to love Jesus. If you love Jesus you will want to tell others about Him and what He has done for you.
You do not have to be a theologian. Consider the blind man in John 9. He told the pharisees what Jesus did for him. “…I was blind but now I see.” The blind man deduced that Jesus was a prophet and a man from God with what had been done for him. He related that to the pharisees. We should tell others based on our knowledge of Jesus without regard to the depth of our knowledge. Of course after becoming a Christian there should be a natural desire to become more knowledgeable.
Some evangelism can be done through lifestyle. We serve a gracious and loving God so if we are gracious and loving to others then we become attractive and sometimes we get to share our beliefs with others when others become curious as to why we are gracious and loving. This can be tough because we often sin and others see that as well as our Christlike behavior.
At any time we evangelize we should seek God’s guidance and support through prayer. It is God who saves - not us. However, God most often uses us as His means in reaching the lost.
Evangelism Explosion training (EE) is an excellent tool to use in sharing our faith. EE is a very convincing method in telling others about Jesus. I have used it to share with hundreds of people and seen dozens make professions of faith after hearing the Gospel message in the EE presentation.
When I received EE training it took about 12 weeks with weekly assignments and weekly team visits where the Gospel is presented by your trainer until you have begun to master the material. Some trainees will be ready to present in just a couple of weeks, but most need the full 12 weeks. There is additional training beyond the 12 weeks for those inclined. It has been 20 years since I first took EE so lessons and training may have changed some.
Interestingly, while I received substantial apologetic training through EE, I hardly ever remember using apologetics in any visit. Maybe two times. What was needed more than anything was the Holy Spirit, prayer, and a modicum of boldness which the Holy Spirit will supply.