The most important thing is that you share the Good News (Gospel). This is simple. All these other things may help, but it is the proclamation of the Gospel that transforms minds. See Give Them the Gospel.

Christian witness to those outside of the Body of Christ is the flow of God's love to those whom He has created. This witness may use words, but it will not consist primarily of words. Too many Christians are trying to bring people to Christ by an overpowering personality or high-pressure salesmanship. The Bible says that it is the love between the members of the Body of Christ that is one of God's primary methods of causing the world to believe.

It's as true in Bible witness and Christian witness as in any other area that argument is fruitless. In sales, they say that if you win the argument you will lose the sale. In Bible witness, you can easily turn people away from Christ rather than winning souls to Christ.

There are many who are being convicted by the Holy Spirit right now to come to Christ or come to a better understanding of Christ. We Christians must continue to testify of Jesus by His holy power in us. Pray that God prepare your heart so that you can say His words and that the grace of God flows through you in power. Pray that the Holy Spirit goes before you to do the work.

Never assume that you are the one doing the work. If the work is to be anything, God must do the work through you. You cannot save anyone. You are a witness, and a vessel. The Holy Spirit is the One who does the work. He does His work through you to the extent that you are able to submit yourself to Him. He will make your mind alive and give you the words of life. That does not mean that you don't prepare yourself for ministry and witness. It means that you stay in the Spirit with the Spirit flowing through you at all times, working, sleeping, playing, studying, witnessing, or whatever you are doing.

As the wheat and tares are growing together, it seems that the tares are becoming quite mature and poisonous. In the Church, I believe that we need to pray that we are also brought to maturity in Christ. It seems that a life that is without contradiction in righteousness is what the Atheist and Agnostic must see. I'm convinced that they are not seeing this very often, and the lives of Christians only confirm their godless opinion that there is no God, no Jesus, and no salvation.

If you come across a rabid Atheist or evolutionist or old-earther or anti-Bible person, just say the obvious. First, tell them that every evidence against God or the Bible, and every evidence for evolution and an old earth/Universe, is based on one of the following: a made-up story, an arbitrary assumption, an outright lie, or a irrational statement. Sometimes, you have to check it out, but you will find that it's always true.

Then tell them that any one who follows Christ believes Christ and all His revelation because Christ reveals it to us. Christ reveals Himself to us. He speaks to us through many means. We discern His Voice. In fact, "faith comes by hearing and hearing comes by the word (Greek: rhema = utterance) of God." Christ leads and we follow. He is a Person, not a theory or a belief.

So the discussion is about made-up and crazy stuff versus reality.

They don't like it, but all they can answer with is a made-up story, an arbitrary assumption, an outright lie, or a irrational statement. When they do answer, Just thank them for another fine example and show them that they need Jesus because they are sinners just like everyone else.

Here is an excellent resource for your Christian witness:
https://www.christianwitnessingtools.com Christian Witnessing Tools Training & Ideas Christian witnessing tools and techniques to share your faith using 5 key words in John 3:16.

As long as YOU are the message, you can never be the MESSENGER.

Be a fountain, not a drain.

Be careful how you live. You may be the only Bible some people read.