There are many avenues leading to witnessing. God is unlimited in the ways His wonders to perform. One of the greatest wonders of God is His calling and choosing of those for salvation. The last one will be given by a great angelic evangelist, to the whole world! (Revelation 14:6).
When the church in Judea and Jerusalem was scattered by the persecution after Pentecost, many of those who were scattered became "witnesses" for Jesus Christ. They did so by their light and by their word. So many believed because of the way they lived their lives, and it was such an effective witness that a second church headquarters became necessary for the expansion of the gospel.
That second "headquarters" was Antioch. Most of the Christians in that original church were not converted by powerful preaching by well know evangelists, until the Apostle Paul and others made Antioch their home base. This church was populated by common people, from many areas - even other countries, who lived the life of God before their countrymen and neighbors. Many asked of them a reason for the hope that dwelled in them. Many answered. And the Antioch church - and others - grew. The spread of the gospel of Jesus Christ had begun in a very big way.
In those early days of the spreading of the gospel, most came to believe by the example of those who had been scattered. Their lives spoke the gospel for them. Nothing teaches quiet as effectively as example - both good and bad. When they were asked why they lived as they did, they gave the answer. They had become enabled by the Holy Spirit to give an answer. The answer only contributed to the larger witness of the fruit of their lives of love and righteous living that others could see. It was mostly what others saw. Then, they could hear words. They saw light. Then they heard words. It is no different in many parts of the world today.
There is a saying that "words are cheap", but doing is very expensive. Unbelievers will see you before they hear you. You must be sure the two do not contradict. Be sure one does not contradict the other. Which one are others most likely to believe - what they hear from you, or what they see you do? As was asked in a popular motion picture some years ago, "are you going to believe what you see, or are you going to believe what I tell you"?
If you were in their shoes, what would you believe first? So when do you add words to your light? When you are asked! This is important since words only - when put forth without being invited - can be terribly misunderstood. Only when someone has already seen the light in you will they yield to being led to Christ by the Father. And of course, no can come to Jesus unless the Father through the Holy Spirit leads them. This is very important to keep in mind (John 6:44). Also, all that the Father chooses will come to Jesus (John 6:37). The reason that you can be enabled to give an answer for the hope you have as a Christian is because the Father has already prepared that one by the Holy Spirit, and by their seeing the light in your life.
They will eventually ask someone whose light they have observed, about their hope that lies within. They have no reason to ask, unless they see something that provokes a question. There are circumstances, however, when someone not well known by an unconverted person can be approached with words that eventually bare fruit in repentance and believe. However, this often backfires. It becomes the fulfillment of the poetic phrase "he that is convinced against his will, is of the same opinion still". It can, for the moment, be against God's timing. However, some will receive the planted seed on good ground, and eventually come to repentance and belief in Jesus as their Savior (Mark 4:3-8).
The overarching reality that must be kept in mind in the whole issue of witnessing is the silent working of the Holy Spirit. In the life and mind of the one witnessing, and in the heart and mind of the one being witnessed to. If you are led by the Holy Spirit, He will prompt you if and when to give a verbal reason for the hope that lies within you. Until then, let you light be so bright in the eyes of those who see your life that they must ask you about your belief in Christ.
Now its time for words.
"You are the light of the world. A city set on a hill cannot be hidden. Nor do men light a lamp and put it under a peck measure, but on a lampstand, and it gives light to all in the house. Let your light so shine before men that they may see your moral excellence and your praiseworthy, noble, and good deeds and recognize and honor and praise and glorify your Father Who is in heaven." - Matthew 5:14-16 (AMP)
"But in your hearts set Christ apart as holy [and acknowledge Him] as Lord. Always be ready to give a logical defense to anyone who asks you to account for the hope that is in you, but do it courteously and respectfully.
- 1 Peter 3:15 (AMP)