1) You will never evangelize the person you do not speak to. Some have attributed the saying "Preach the the Gospel at all times, if necessary use words." to St. Francis of Assisi. While attributing the saying to him may be debated, the saying is outright misleading. It implies that Christians should live out the Gospel through acts of kindness, grace, love, forgiveness and charity towards everyone, and these deeds will show non-believers the Gospel. While it would be an understatement to say that "faith without works is dead" (James 2:20), one would need to understand what is being said here. Ray Comfort once stated that using this popular saying is akin to seeing starving children and exclaiming "feed the hungry - if necessary, use food." Can unbelievers call upon Jesus if they have not believed in Him? No. (Rom. 10:14) Can unbelievers experience salvation without hearing the Gospel? No. (Rom. 10:14) How do unbelievers become acquainted with the precious message of the Gospel? Through the hearing of the Word of God and the audible sharing of the Gospel of Jesus Christ. (Rom. 10:14, 17) Of course your life should reflect the Gospel in such a magnificent way that that way you treat others causes them to recognize something distinctly different about you. Your words will give glory to God and answer the questions "Why does this person act/treat me differently?" and "What hope/purpose is there in this life?" You can't answer these questions, nor present the Gospel with anyone you don't intentionally speak with. I know it's scary, but I'm learning to open my heart and open my mouth to others about the hope we share.
2) We speak out of the overflow of our hearts. Proverbs 4:23 states "Above all else, guard your heart, for it is the wellspring of life." If we're constantly in the Word of God, serving others, doing missions, serving at Church, praying, and glorifying God, these things will naturally come up in our conversations with non-believers. It's when we focus on ourselves all day, that we talk about ourselves all day. When seeking to find ways to move a conversation to things of God from seemingly unconnected things, talk about your day. What did you learn from/about God when reading the Bible today? What did you learn about how God views people and about God Himself by serving in the nursery, teaching Sunday School, or working at the local shelter? Our purposeful acts of worship and obedience are perfect ways of swinging a conversation from the natural realm to the spiritual.
3) You may not argue someone into believing in Christ, but you most certainly can love and forgive them like Christ in the process. I've had many arguments that I walked away from feeling like I "won" regarding my arguments for God and the Christian faith, but if my attitude in discussing left the person cussing, then I think I've lost in a much more vital way. Our concern for a lost person's eternal state of their soul should always be what others see, not our knowledge. The Apostle Paul even stated that at times he would throw off all knowledge and resolve to know nothing but Christ and him crucified among the people he was ministering to. (1 Cor. 2:2) Why would Paul do that? So that they wouldn't see a puffed-up believer, but an earnest follower of Christ seeking reconciliation to God for those who were as he once was. Of course there is a place for logical arguments and sculpted apologetics, but never at the sake of showing God's love. I have to remind myself that it is as D.T. Niles once put it, "one beggar telling another beggar where the food is." While this may be a very limited definition of evangelism, it should present the image of us meeting real needs for real people, and earnestly seeking to do this out of obedience and compassion.
Perhaps C.H. Spurgeon said it best exhorting "If sinners are to be damned, let them leap over our bodies to do so." Please open your mouth and tell someone about Christ today. You'll always be glad you did!